I'm working on a new client's website that loads Javascript from a CDN so the Javascript is not embedded or inline with the webpage source. I would like to pause everytime getCurrentPosition() is executed in order to determine which external JS file it is contained in.
I realize I could use other tools to do a string search through the contents of the JS files but I would rather keep to Chrome's debugging tools.
Should I be trying to create a watch expression or is there another way to pin down when and where a certain JS function is fired?
You can search in all files using Chrome DevTools. Find your function and debug it:
Open DevTools (F12)
Go to sources tab
Open Search All Files by pressing ctrl + shift + f (Win) or cmd + option + f (Mac)
Search getCurrentPosition
Put a breakpoint (By clicking the line number at the left of the line)
Open Google Dev tools(F12)
Press Ctrl + p
In the opened box search for all files(JS, CSS, ...).
In the box you have 5 options:
At the first select a file for using options 2-5
Type 'filename' and select it.
Type ':linenumber' to go to specific line number(':10' go to line 10).
Type '#symbol' to go to specific symbol('#TestSymbol' go to TestSymbol symbol).
In this option, if you write #JSFunctionName or #CSSClassName then the cursor
will navigate to the JSFunctionName or the CSSClassName.
Type '!snippet' to go to specific snippet('!snippetTest' go to snippetTest snippet).
Type '>googleCommand' to go to specific command('>Clear console' clear the console).
You can find all the information that you need at the webpage: https://developer.chrome.com/devtools/docs/javascript-debugging
By simply putting it (copied from the webpage)
Open a site such as the Google Closure hovercard demo page or the TodoMVC
Open a site such as the Google Closure hovercard demo page or the TodoMVC Angular app
Open the DevTools window.
If it is not already selected, select Sources.
Debugging with breakpoints
A breakpoint is an intentional stopping or pausing place in a script. Use breakpoints in DevTools to debug JavaScript code, DOM updates, and network calls.
Add and remove breakpoints
In the Sources panel, open a JavaScript file for debugging. In the example below, we are debugging the todoCtrl.js file from the AngularJS version of TodoMVC.
Click the line gutter to set a breakpoint for that line of code. A blue tag will indicate if a breakpoint has been set:
With the above simple example you can actually "stop" the function getCurrentPosition() and debug it.
One way would be to replace the Geolocation.getCurrentPosition method with a wrapper function so that you can set a breakpoint inside it, and then examine the stack to see who is calling it.
If you know where in the code the method is called you can set breakpoints. This will pause the javascript execution during runtime and allow you get a stack trace.
Related
I'm working on a new client's website that loads Javascript from a CDN so the Javascript is not embedded or inline with the webpage source. I would like to pause everytime getCurrentPosition() is executed in order to determine which external JS file it is contained in.
I realize I could use other tools to do a string search through the contents of the JS files but I would rather keep to Chrome's debugging tools.
Should I be trying to create a watch expression or is there another way to pin down when and where a certain JS function is fired?
You can search in all files using Chrome DevTools. Find your function and debug it:
Open DevTools (F12)
Go to sources tab
Open Search All Files by pressing ctrl + shift + f (Win) or cmd + option + f (Mac)
Search getCurrentPosition
Put a breakpoint (By clicking the line number at the left of the line)
Open Google Dev tools(F12)
Press Ctrl + p
In the opened box search for all files(JS, CSS, ...).
In the box you have 5 options:
At the first select a file for using options 2-5
Type 'filename' and select it.
Type ':linenumber' to go to specific line number(':10' go to line 10).
Type '#symbol' to go to specific symbol('#TestSymbol' go to TestSymbol symbol).
In this option, if you write #JSFunctionName or #CSSClassName then the cursor
will navigate to the JSFunctionName or the CSSClassName.
Type '!snippet' to go to specific snippet('!snippetTest' go to snippetTest snippet).
Type '>googleCommand' to go to specific command('>Clear console' clear the console).
You can find all the information that you need at the webpage: https://developer.chrome.com/devtools/docs/javascript-debugging
By simply putting it (copied from the webpage)
Open a site such as the Google Closure hovercard demo page or the TodoMVC
Open a site such as the Google Closure hovercard demo page or the TodoMVC Angular app
Open the DevTools window.
If it is not already selected, select Sources.
Debugging with breakpoints
A breakpoint is an intentional stopping or pausing place in a script. Use breakpoints in DevTools to debug JavaScript code, DOM updates, and network calls.
Add and remove breakpoints
In the Sources panel, open a JavaScript file for debugging. In the example below, we are debugging the todoCtrl.js file from the AngularJS version of TodoMVC.
Click the line gutter to set a breakpoint for that line of code. A blue tag will indicate if a breakpoint has been set:
With the above simple example you can actually "stop" the function getCurrentPosition() and debug it.
One way would be to replace the Geolocation.getCurrentPosition method with a wrapper function so that you can set a breakpoint inside it, and then examine the stack to see who is calling it.
If you know where in the code the method is called you can set breakpoints. This will pause the javascript execution during runtime and allow you get a stack trace.
Is there a way to debug the page with browser console or firebug to know how many times
a specific Javascript function is called while loading the page ?
As #SamGreenhalgh pointed out, in Google Chrome, you can simply open the Developer Tools ([Ctrl]+[Shift]+J), find your script in Sources tab, and add
console.count('some label');
right into the body of the function you wish to observe. This will print out
some label: {N}
into the console each time console.count is called at that point with that label (see documentation).
You can set a breakpoint on the function, reload the page, and count how many times you have to press the Continue button.
In the dev tools of most browsers (and in Firebug), you'd do that something like this:
Go to the page
Open the dev tools (via menus, or press F12 on most browsers, etc.)
Navigate to the "Source" pane (the name varies, but it's usually something like that)
Find the function in the scripts. (Chrome's dev tools have a great feature: Ctrl+Shift+F does a search through all loaded scripts.)
Click the gutter to the left of the function to set a breakpoint
Then reload and count. I'm not aware of an automated way to do it.
I am using bootstrap modal, I dont know where I have put the js code that triggers the modal after clicking the button.
jQuery('#signin').modal('show');
I checked each file...even checked each JS file in source in browser.
How can I find which code is triggering the event in browser when I am clicking the button to open a modal?
Use a developer tool for a browser which will allow you to perform Javascript debugging. Your best bet is most likely Firebug. If you set a debug point at a line within a JS file, firebug will allow you to inspect the stack to see which line has called the function.
Instructions
In Firebug, click the script tab.
Select your .js file using the drop down.
When the JS file displays find the target line and click to the left of it, setting a debug point.
Load your page, the script should stop at your debug point.
Click the Stack tab on the right and inspect.
Searching for Script in Firebug
If you click the script tab you can enter a known piece of the script in the upper right hand corner of firebug, this should take you to its location in the code.
I agree with Kevin, another option is to print the stack trace using something like:
http://www.codeovertones.com/2011/08/how-to-print-stack-trace-anywhere-in.html
Is there anyway that I could trace/see the exact order that a website is processed across html, css and javascript?
I have a function that is not firing off on the first pass and I'm pretty sure it has to do with the order of execution.
but also, it would be very informative to see the individual steps as they are processed (slowly)
Thanks for any advice.
this is in relation to this question:
flashMovie.Play is not a function
It sounds as if you want to set up breakpoints in your code, and then step through the execution path.
Click on the Wrench symbol on the top right of the Chrome screen, select Tools, and select Developer Tools
Click on the Scripts tab on the bottom pane of the Chrome Screen
Click on Folders on the top left corner of the bottom pane of the Chrome Screen
Click on the script that you want to debug
Click on the line that want to setup the breakpoint
The Chrome Developer Tools official documentation is also available here: https://developers.google.com/chrome-developer-tools/docs/scripts
Once you have hit the desired breakpoint (which could just be the first line of the script), the click on the "Step into next function call" (it looks like a down arrow pointing to a dot) button on the top right section of the bottom pane of the Chrome screen.
These questions should help as well:
How to step through code in Google chrome javascript debugger
How to set breakpoints in inline Javascript in Google Chrome?
Javascript breakpoints not working in Chrome Developer Tools
Set a breakpoint in XHR in Chrome
In Chrome, use the Developer Tool Bar. Press the Keyboard Key: F12.
Place an alert(1); or console.log(2) in your JS and see what happens. If you use Firefox start with opening its web console and look if you get any errors there. Ctrl+Shift-K to open the Web Console.
Press F12 OR Ctrl+Shift-K for developer tools, it works almost in any browser. you will be debug your code and use consol
I am using javascript for an ascx control in my application.
I am getting some errors and want to debug the same.
I have put the debugger in my javascript and unchecked disable script debugging for internet explorer.
When my script is getting executed, I get the debugger launched, and when I attach the javascript (here it is in a separate file ), There is a message as,
There is no source code available for the current location.
What could be going wrong here.
I hope to get some tips on debugging javascript with ascx control
To debug Javacript embedded in a ascx control, you can use chrome explorer.
Here is the step.
Open the page that has the user control in it.
Press F12 on that page.
go to Sources in the "DevTools"
Find pages in the "Sources" tab
click on the page name that you are debugging.
you will see the source code in the middle pane.
your user control javascript is included in the page's source code, this is the key.
use Ctrl + F to find that javascript by the method name you want to debug
add breakpoints to that method and debug
Hope it helps.
To debug JavaScript, Hit f12 in your browser. This will open the developer tools in most browsers. (with Firefox, this assumes you've already installed firebug, which has to be installed separately as an add-on.)
Select the script tab, set your break points by clicking the margin to the left of the line of code where you want to break. If you are using IE, click "start debugging". Then perform an action on your page that will trigger your code. Happy debugging.