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Questions tagged [javascript-debugger]

JavaScript debugger are tools that let you debug your JavaScript code by pausing the execution at any time, step through the code and see what each variable available looks like at that moment.

JavaScript debuggers allow step debugging of JavaScript code. Using them you can set breakpoints within the code. When a line of code is executed, which has a breakpoint set for it, the execution stops at that line and allows to execute the code step by step.

While stepping through the code the debugger displays all variables available within the current stack frame and typically also allows you to set some watch expressions.

As one of the main use cases for JavaScript are web browsers, different browsers have integrated tools to debug JavaScript. These tools are:

Furthermore IDE's like NetBeans or Eclipse also include debuggers for JavaScript.

See also

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Debugging HTML element change upon initial page load by some javascript function, but unable to find it.

I know chrome has a javascript debugger where you can set break points in the HTML if anything gets modified, but your only able to do this when the page has already loaded. I'm trying to figure out how an element is being assigned a inline style…
Patoshi パトシ
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How to get Chrome debugger to break or error when working on undefined variables

My Javascript code (hundreds of lines) hangs Chrome and when I debug the issue I find out that a variable was undefined. I don't get errors in the console. So this is making my debugging more time consuming because there are no errors or exceptions…
Tony_Henrich
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How to extend console.log which can accept args without using additional ()?

I've been working on extending console.log to make a colorful one that keeps the stack trace as to where it has been called. I've tried some solutions, but finally reach this point: const colorizedLog = (text, color= "#40a7e3", ...args) => …
SeyyedKhandon
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ios Could not get BatchedBridge, make sure your bundle is packaged properly

I am getting this while running app on simulator using xCode, version 9.2 I've tried other solution mentioned on Stack overflow & Github S1S2 S3 S4 but most of the solution are mentioned for android. P.S. This project also includes purescript code…
Zubair
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how to edit Javascript in Html in Chrome Dev Tools

We can edit and execute JavaScript code from the *.js file in the Sources panel of Chrome DevTools. However, if the js code comes from the *.html file, how can we edit and execute them besides adding breakpoints?
kevin_chen
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How can I activate the Firefox debugger?

While debugging a JavaScript program I was writing with Firebug, the Script panel stopped working and I got the following message: I went through all menus and sub-menus I could find but didn't see a option to re-enable this feature. The…
Math chiller
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Request for wsTestService.asmx/jsdebug returns 500 error on server, fine in development

Folks, I have a simple test application in which I return a string from a web service without arguments. This works fine under my development environment (VS 2010 SP1Rel on Windows 7 64 bit). When I deploy to the local IIS7 the proxy code for the…
bnieland
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Chrome CPU profile not storing sourcemaps details?

I am using chrome's Javascript Profile to store the cpuprofile's. When we capture a cpu profile in chrome, it reads details of source map and shows the path & line number of the actual source file, similar to as shown below. However, if I save the…
Sumit Paliwal
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Is there a browser API to get a list of page resources?

I'm working on a remote JavaScript debugger and page inspector. I'm trying to find a way to programmatically get a list of all page assets (stylesheets, scripts, images, fonts, etc.) that a page loads, and pass them along to the remote inspector.…
colbin8r
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Run JSLint on a .js file from debugging console in chrome or firefox

Is it possible to run JSLint on one or more .js files by having JSLint loaded afterwards in the header from debugging/developer console in chrome or firefox? The reason that I want to do that is that I want to print in console.log() the parsing of…
Eduard Florinescu
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How do I find/profile what JavaScript is being executed "right now" using Firebug or any other way?

I am studying this page: http://www.fxstreet.com/rates-charts/currency-rates/ which is continually updated by JavaScript with new data from the server. So clearly there is some JavaScript function continually executing in the page. So I opened…
EndangeringSpecies
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Error Debugging in VS Code: Cannot connect to the target at localhost:3000: could not find any debuggable target

I have an application with React on frontend and .Net Core on backend and i am trying to debug my react frontend, without extensions and attaching to the process, but i am getting the message error bellow: Cannot connect to the target at…
Jean Vidal
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How to set a breakpoint in standard/native JavaScript functions?

Can I set a breakpoint on a standard JavaScript function? For example, can I pause the debugger every time context.beginPath() is called? Or every time that String.replace() is called? UPDATE: What I meant by standard JavaScript function is…
kiewic
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How to view the value of a variable in Firefox Developer Edition 52.0a2?

In the Debugger in Firefox Developer Edition I've set a breakpoint to land on the assignment to a JavaScript variable. I expected to be able to hover over all previously defined variables to view their values within a tooltip like in previous…
CerIs
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WCF javascript proxy not found when endpoint address is not blank

I am trying to setup a WCF service with multiple endpoints with one of the endpoints using the enableWebScript endpoint behavior so that a Javascript proxy will be created on the client (jsdebug/js). When adding the Service Reference to my AJAX…
John Oswalt
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