Use breakpoints to pause your JavaScript code. This article explains each type of breakpoint available in DevTools, as well as when to use and how to set each type. For an introductory tutorial using an existing webpage, see Get started debugging JavaScript. The most well-known type of breakpoint is line-of-code. But line-of-code breakpoints may be inefficient to set, especially if you don't know exactly where to look, or if you are working with a large codebase. You can save yourself time when debugging by knowing how and when to use the other types of breakpoints. Use this when you want to pause... On an exact region of code. On an exact region of code, but only when some other condition is true. On the code that changes or removes a specific DOM node, or the children. When an XHR URL contains a string pattern. On the code that runs after an event, such as click, runs. On the line of code that is throwing a caught or uncaught exception. Whenever a specific command, function, or method is run. A variant that does not "break" into the debugger but instead logs a message to the console. Use a line-of-code breakpoint when you know the exact region of code that you need to investigate. DevTools always pauses before this line of code is run. To set a line-of-code breakpoint in DevTools: Select the Sources tool. Expand the XHR/fetch Breakpoints panel. Click Add breakpoint. Enter all or part of the URL that you want to break on. DevTools pauses when the value you enter is present anywhere in an XHR or Fetch request URL. Press Enter to confirm. Use event listener breakpoints when you want to pause on the event listener code that runs after an event is fired. You can select specific events, such as click, or categories of events, such as all mouse events. Select the Sources tool. Expand the Event Listener Breakpoints panel. DevTools shows a list of event categories, such as Animation. Select a category, to pause whenever any event from that category is fired. Or, expand the category, and then select a specific event: Use exception breakpoints when you want to pause on the line of code that is throwing a caught or uncaught exception. Select the Sources tool. To pause when the code throws a JavaScript exception, in the Breakpoints pane, select the Pause on uncaught exceptions checkbox. Run the debug(function) method, where function is the JavaScript function that you want to debug, when you want to pause whenever a specific function is run. You can insert debug() into your code (such as when using a console.log() statement), or run the method from the DevTools Console tool. debug() is equivalent to setting a line-of-code breakpoint on the first line of the function.

This article covers how to use the debugger features in Microsoft Edge DevTools, including how to set a line-of-code breakpoint. See also: Get started debugging JavaScript - tutorial walkthrough. Pause your code with breakpoints - setting various types of breakpoints. When fixing a bug, you often want to try out some changes to your JavaScript code. You don't need to make the changes in an external editor or IDE, re-upload the file to the server, and then refresh the page; instead, to test changes, you can edit your JavaScript code directly in DevTools and see the result immediately. To view and edit a JavaScript file: Open the webpage you want to debug in a new window or tab. You can use the Get Started Debugging JavaScript demo page. To open DevTools, right-click the webpage, and then select Inspect. Or, press Ctrl+Shift+I (Windows, Linux) or Command+Option+I (macOS). DevTools opens. In DevTools, on the Activity Bar, select the Sources tab. If that tab isn't visible, click the More tools () button. In the Navigator pane, select the file you want to change, to open it in the Editor pane. If you're using the demo page, select get-started.js. In the Editor pane, edit the file. For example, add alert("The add button was clicked"); in the onClick function of the demo page. Press Ctrl+S (Windows, Linux) or Command+S (macOS) to save. DevTools then loads the JavaScript file into the JavaScript engine of Microsoft Edge, and the changes take effect immediately. To learn how to pause at a breakpoint, see Set a breakpoint, to pause code, above. When paused on a line of code containing a function that isn't relevant to the problem you are debugging, click the Step over () button to run the function without stepping into it. For example, suppose you are debugging the following code snippet: var addend1 = getNumber1(); // A var addend2 = getNumber2(); // B var sum = addend1 + addend2; // C label.textContent = addend1 + " + " + addend2 + " = " + sum; function getNumber1() { return inputs[0].value; function getNumber2() { return inputs[1].value; You are paused on A. After you click Step over, DevTools runs all the code in the getNumber1() function and then pauses on B. If you click Step over again, DevTools run all the code in the getNumber2() function and then pauses on C. When paused on a line of code containing a function call that is related to the problem you are debugging, click the Step into () button to investigate that function further: For example, suppose you're debugging the following code: var addend1 = getNumber1(); // A var addend2 = getNumber2(); var sum = addend1 + addend2;

This article teaches you the basic workflow for debugging any JavaScript issue using DevTools. The first step in debugging is to find a sequence of actions that consistently reproduce a bug. Open the demo webpage Get Started Debugging JavaScript in a new window or tab. To open the webpage, right-click the link and select "Open link in new tab" or "Open link in new Window" on the popup window. Alternatively you can press and hold Ctrl (for Windows, Linux) or Command (for macOS), and then click the link. Tip: Open Microsoft Edge in InPrivate Mode, to ensure that Microsoft Edge runs in a clean state. For more information, see Browse InPrivate in Microsoft Edge Enter 5 in the Number 1 text box. Enter 1 in the Number 2 text box. Click Add Number 1 and Number 2. The label below the button says 5 + 1 = 51, instead of the expected result of 6: DevTools provides several tools for different tasks. These tasks include changing CSS, profiling page-load performance, and monitoring network requests. The Sources tool is where you debug JavaScript. To open DevTools, right-click the webpage, and then select Inspect. Or, press Ctrl+Shift+I (Windows, Linux) or Command+Option+I (macOS). DevTools opens: Select the Sources tool. Select the Page tab, and then select the JavaScript file, get-started.js: The Sources tool UI has three parts: The Navigator pane (in the upper left corner). Every file that the webpage requests is listed here. The Editor pane (in the upper right corner). After you select a file in the Navigator pane, this pane displays the contents of the file. The Debugger pane (at the bottom). This pane provides tools for inspecting the JavaScript for the webpage. If your DevTools window is wide, this pane is displayed to the right of the Editor pane. A common method for debugging this type of problem is to insert several console.log() statements into the code and then to inspect values as the script runs. For example: var addend1 = getNumber1(); console.log('addend1:', addend1); var addend2 = getNumber2(); console.log('addend2:', addend2); var sum = addend1 + addend2; console.log('sum:', sum); Event Listener Breakpoints let you do that: In the Navigator pane, (index) is selected by default. Click get-started.js. In the Debugger pane, click Event Listener Breakpoints to expand the section. DevTools reveals a list of event categories, such as Animation and Clipboard. Click Expand () by the Mouse event open that category. DevTools reveals a list of mouse events, such as click and mousedown. Each event has a checkbox next to it. DevTools is now set up to automatically pause when any click event listener runs. In the rendered demo webpage, click the Add Number 1 and Number 2 button again. DevTools pauses the demo and highlights a line of code in the Sources tool. DevTools pauses on line 16 in get-started.js, shown in the next code snippet: If you pause on a different line of code, click Resume Script Execution () until you pause on the correct line. If you paused on a different line, you have a browser extension that registers a click event listener on every webpage that you visit. You are paused in the click listener of the extension. If you use InPrivate Mode to browse in private, which disables all extensions, you might see that you pause on the desired line of code every time. Event Listener Breakpoints are just one of many types of breakpoints available in DevTools.

With a debugger, you can also set breakpoints (places where code execution can be stopped), and examine variables while the code is executing. Normally (otherwise follow the steps at the bottom of this page), you activate debugging in your browser with the F12 key, and select "Console" in the debugger menu. If your browser supports debugging, you can use console.log() to display JavaScript values in the debugger window: Tip: Read more about the console.log() method in our JavaScript Console Reference. In the debugger window, you can set breakpoints in the JavaScript code. At each breakpoint, JavaScript will stop executing, and let you examine JavaScript values. After examining values, you can resume the execution of code (typically with a play button). The debugger keyword stops the execution of JavaScript, and calls (if available) the debugging function. This has the same function as setting a breakpoint in the debugger. If no debugging is available, the debugger statement has no effect. With the debugger turned on, this code will stop executing before it executes the third line. Normally, you activate debugging in your browser with F12, and select "Console" in the debugger menu. Otherwise follow these steps: Open the browser. From the menu, select "More tools". From tools, choose "Developer tools". Finally, select Console. Open the browser. From the menu, select "Web Developer". Finally, select "Web Console". Open the browser. From the menu, select "Developer Tools". Finally, select "Console". Open the browser. From the menu, select "Developer". From "Developer", select "Developer tools". Well organized and easy to understand Web building tutorials with lots of examples of how to use HTML, CSS, JavaScript, SQL, Python, PHP, Bootstrap, Java, XML and more.

So, in this article, we will learn how to debug JavaScript in Microsoft Edge. To start with debugging, we need to perform some actions to reproduce a bug. For demonstration purposes, here We have the code to add two numbers. label.textContent = "Error: one or both inputs are empty."; Now, it is not giving the correct result in the output as you can see, so we will check what is the error. Moving on to the next step, we will try to get familiar with the sources tool UI Microsoft edge provides us with different developer tools to perform different tasks. To open Developer tools, right click anywhere on the webpage and click on “Inspect” Select the “Sources” tool. It comprises of three parts:- The pane in the upper left corner is called the Navigator tab. It lists down all the files that a webpage has requested. It is also called the page tab. To debug the code, from the navigator tab, select your JavaScript file. Here, We will select get-started.js File. The contents of the file will now be visible in the editor pane, as you can see in the image above. The window at the bottom is called the debugger pane and it provides us with the tools to debug the JavaScript code. Now coming to the actual part i.e. debugging the code, we need to see where is the error. A common approach to find error is marking breakpoints. It is an alternative for console.log () statement but a little less time consuming than that. So, let’s apply breakpoints to our code and check where is the error. As shown in the image above, our output is displayed when the button is clicked. his tells us about the occurrence of an event. Hence, we will make use of an event listener breakpoint. Scroll a little and click on Event listener breakpoints. Then rightclick on “mouse” as this event is happening on mouse click. Now, tick the checkbox “click”. By doing this, your dev tools will automatically pause whenever any mouse click will happen. Now when you’ll rerun the code and click on ADD button, your code will auto pause as soon as the mouse click happens. Stepping through your code allows you to walk through the runtime of your code and hence helps you understand it better. Click Step over next function call. DevTools will run the following code without stepping into it. On the Sources tool of DevTools, click Step into next function call to step through the runtime of the updateLabel () function, one line at a time. Line-of-code breakpoints are another common types of breakpoints applied at specific line of code where one wants to pause. As you can see in the screenshot above, at line number 20 there is a red circle next to the code. This indicates the line of code breakpoint. Devtools will always pause before this line of code as it could be seen above. When you’ll click on Resume script execution, the play button in the debugger pane, then only the code will resume. The values of the variables at that point could be seen at the bottom right pane, as shown in the image above. Now, the values of variables returned in the above step doesn’t seem correct.

This article explains each type of breakpoint available in DevTools, as well as when to use and how to set each type. For an introductory tutorial using an existing webpage, see Get started debugging JavaScript. The most well-known type of breakpoint is line-of-code. But line-of-code breakpoints may be inefficient to set, especially if you don't know exactly where to look, or if you are working with a large codebase. You can save yourself time when debugging by knowing how and when to use the other types of breakpoints. Use this when you want to pause... On an exact region of code. On an exact region of code, but only when some other condition is true. On the code that changes or removes a specific DOM node, or the children. When an XHR URL contains a string pattern. On the code that runs after an event, such as click, runs. On the line of code that is throwing a caught or uncaught exception. Whenever a specific command, function, or method is run. A variant that does not "break" into the debugger but instead logs a message to the console. Use a line-of-code breakpoint when you know the exact region of code that you need to investigate. DevTools always pauses before this line of code is run. To set a line-of-code breakpoint in DevTools: Select the Sources tool. Use a DOM change breakpoint when you want to pause on the code that changes a DOM node or the children. To set a DOM change breakpoint: Select the Elements tool. Go the element on which you want to set the breakpoint. Subtree modifications. Triggered when a child of the currently selected node is removed or added, or the contents of a child are changed. Not triggered on child node attribute changes, or on any changes to the currently selected node. Attributes modifications: Triggered when an attribute is added or removed on the currently selected node, or when an attribute value changes. Node Removal: Triggered when the currently selected node is removed. Use an XHR/fetch breakpoint when you want to break when an XmlHttpRequest (XHR) or Fetch request occurs. DevTools pauses on the line of code where the XHR or Fetch request occurs. One example of when this is helpful is when your webpage is requesting an incorrect URL, and you want to quickly find the XHR or Fetch source code that is causing the incorrect request. To set an XHR breakpoint: Select the Sources tool. Expand the XHR/fetch Breakpoints panel. Click Add breakpoint. Enter all or part of the URL that you want to break on. DevTools pauses when the value you enter is present anywhere in an XHR or Fetch request URL. Press Enter to confirm. Use event listener breakpoints when you want to pause on the event listener code that runs after an event is fired. You can select specific events, such as click, or categories of events, such as all mouse events. Select the Sources tool. Expand the Event Listener Breakpoints panel. DevTools shows a list of event categories, such as Animation. Select a category, to pause whenever any event from that category is fired. Or, expand the category, and then select a specific event: Use exception breakpoints when you want to pause on the line of code that is throwing a caught or uncaught exception. Select the Sources tool. To pause when the code throws a JavaScript exception, in the Breakpoints pane, select the Pause on uncaught exceptions checkbox. Run the debug(function) method, where function is the JavaScript function that you want to debug, when you want to pause whenever a specific function is run. You can insert debug() into your code (such as when using a console.log() statement), or run the method from the DevTools Console tool. debug() is equivalent to setting a line-of-code breakpoint on the first line of the function.

How do you resume execution and skip all breakpoints in MS Edge? In Chrome you can click and hold on the "play" button (seen below) to resume execution and ignore breakpoints: You can disable all breakpoints in the F12 tools of Microsoft Edge by hitting Ctrl+Shift+F11. Or, in the Debugger tab of F12, select the Breakpoints tab and click the "disable all breakpoints" button to achieve similar results. Thanks, I didn't know that option was there. In general, all the icons in the debugger are not very intuitive and don't seem to follow typical icon recognition standards. You have to hover over every one to understand what they do. Also, this solution requires me to re-enable breakpoints after I've resumed execution. A feature similar to Chrome's would be nice. How do you resume execution and skip all breakpoints in MS Edge? In Chrome you can click and hold on the "play" button (seen below) to resume execution and ignore breakpoints:

Breakpoints are the points in the code which pause the execution of the code. They are used for debugging or understanding the flow of code. How to set Breakpoints in Edge? Step 1: Open your Microsoft Edge and then open any webpage you want to debug. Then you open the Developer Tools like below. Step 2: Navigate to the Sources tab in developer tools to view and edit your source code. You will find a list of source files on the left of the sources tab. Click on the file you want to set breakpoints in. Click on the line number of the code line to set a breakpoint and pause the execution. Line Breakpoints: To pause execution at a specific line of code. Event Listener Breakpoints: Breakpoints based on specific events to pause execution on the trigger of events in your code. XHR/fetch Breakpoints: Breakpoints on XMLHttpRequest or fetch API to pause execution when data is retrieved or sent. DOM Breakpoints: DOM breakpoints are useful for tracking changes like attribute modifications, node removals, and more. This feature is important for debugging issues related to dynamic page content. Exception Breakpoints: Exception breakpoints are used to pause code execution when an uncaught exception is thrown. You can also pause on caught exceptions by checking into an optional checkbox on the sources tab. Logpoints: This does not break but it logs when a specific breakpoint triggers. Function Breakpoints: Function breakpoints let you pause code execution whenever a specific function is called regardless of its position in the code. Example 1: Let us implement a small example with a button printing a message on click and debug it with breakpoints.

To begin troubleshooting JavaScript errors, you’ll need to access the DevTools. Here are the methods: Right-click Method: Right-click anywhere on the web page and select Inspect. Keyboard Shortcut: Press F12 or Ctrl + Shift + I (Windows/Linux) or Command + Option + I (macOS). Menu Access: Click on the three dots in the upper right corner of Edge, go to More Tools, and select Developer Tools. Once you access the DevTools, you’ll find various panels such as Elements, Console, Sources, Network, and Performance that provide you with different tools for troubleshooting JavaScript errors. The Console panel is one of the most vital tools for debugging JavaScript. It displays messages such as errors, warnings, and logs throughout your JavaScript execution process. When a JavaScript error occurs, it often produces an error message in the Console. Here’s how to check for it: Open the Console panel in DevTools. Observe any messages that appear in red, indicating a JavaScript error. Click on the error message to see the stack trace, which will help you trace the error back to the source code. The stack trace includes the file name and line number where the error occurred. To understand the state of your variables and application flow, you can insert console.log() statements in your JavaScript code. This function writes information or variable values to the Console, helping you identify problems in logic or flow. Example: Log outputs can reveal details about the data your script is processing and help you isolate where things go wrong. Breakpoints allow you to pause the execution of your script at specific points, enabling you to inspect the current state of variables, call stack, and DOM elements. Navigate to the Sources panel in DevTools. Locate your JavaScript file in the file navigator on the left side. Click on the line number where you want to set a breakpoint. You’ll see a blue marker indicating a breakpoint has been set. With the breakpoint set, interact with your web page in a way that will trigger the JavaScript code. The execution will pause when it reaches the breakpoint. While the code execution is paused, you can hover over variables to see their current values or use the Scope pane to observe local and global variables. You can also use the Watch panel to monitor specific expressions or variables as the code executes. Once paused at a breakpoint, you can step through your code using these controls: Step over (F10): Executes the next line of code without entering any function calls. Step into (F11): Enters the function called on the current line, allowing you to debug inside that function. Step out (Shift + F11): Completes the current function execution and returns to the calling function. You can continue running the code without stepping through by pressing the Resume (F8) button. This allows you to continue until the next breakpoint or until the script execution completes. When you encounter an error in the Console, it’s crucial to analyze the error message effectively.

Microsoft Edge Developer Tools, also known as DevTools, provides a suite of features that enable developers to inspect web pages, debug JavaScript, analyze performance, and optimize user experiences. With a user-friendly interface and robust functionalities, these tools empower developers to fix issues quickly and ensure smooth operation of webpages. The first step in debugging JavaScript with Edge DevTools is to open the tools themselves. You can access them in several ways: Keyboard Shortcut: Press F12 on your keyboard. Menu Navigation: Click on the three dots (the More icon) in the upper right corner of the browser, navigate to "More tools," and select "Developer tools." Context Menu: Right-click on any part of the webpage and select "Inspect." Once you open the DevTools, you’ll notice several tabs, including "Elements," "Console," "Debugger," and "Network," each providing significant features for debugging. The Elements tab allows you to see and manipulate the HTML and CSS of a page in real time. You can modify the structure, styles, and layout of the webpage. This is useful for checking how your JavaScript interacts with HTML elements. The Console is a vital tool for debugging JavaScript. It allows you to execute JavaScript commands in the context of the current page, displaying output and errors produced by your scripts. This tab is also where you will receive error messages if your JavaScript encounters problems. The Debugger is where the serious debugging takes place. It provides a view of your JavaScript code, allowing you to set breakpoints, step through code, inspect variables, and understand the flow of execution. The Network tab displays all network requests made by your webpage, including AJAX calls and resource loading. Setting breakpoints is a powerful way to control the execution of your JavaScript and inspect the code at specific points. Navigate to the Debugger Tab: The Debugger tab displays all your JavaScript files loaded into the current page. Set a Breakdown Point: Find the script file you want to debug and click on the line number where you want the execution to pause. A blue marker will indicate the breakpoint. Refresh the Page: Once you refresh the page, the execution will pause when it hits the breakpoint. You can then inspect variables and the overall state of the code. Once you’ve hit a breakpoint, you can step through your code line by line using the following controls: Continue (F8): Resumes execution until the next breakpoint. Step Over (F10): Executes the next line of code but doesn’t enter any function calls. Step Into (F11): Steps into any function call to see its code. Step Out (Shift + F11): Executes the rest of the current function and pauses when it returns. This functionality allows you to thoroughly examine how variables change over time and how functions are called. As you step through your code, you can inspect the values of variables. The right sidebar in the Debugger tab will show the Scope Variables and Call Stack when execution is paused. Watch Expressions: You can add any variables or expressions to the “Watch” list to monitor them while debugging.