Any JavaScript code can be debugged using the allert() box .log the debug pointer in the debugger() or the console.
Place a warning box in the code where you want to check the flow or any variable values.
For example, aert ('message to show') plus variable);
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Development/debugging tools:
Debugger is the most important tool for developers to check for problems and errors in their code when developing.
Ext JS is a JavaScript framework, so it can be easily debugged using development tools that are available from different browsers or specific.
All major browsers have their own development tools for testing and debugging JavaScript code.
Popular debuggers are IE's IE development tool, firefox's firefox, Chrome's chrome development tool.
Chrome debugger brings its own Chrome browser, but firebugs must be specifically installed because it is not as a package with firefox.
Here is a link to the firefox
browser http://getfirebug.com the
firebug
The shortcut to opening a development tool in the Windows operating system is the F12 keyboard key.
How to debug JS code in the debugger:
There are two ways to debug JavaScript code
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Place the console file in .log and see the value of the log that will be printed in the development tool console.
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Use break points in development tools:
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Open the file in all available scripts under the script label
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Now place a break point on the line you want to debug
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Run the application in the browser
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Now every time the code flow reaches this line, it breaks the code and stays there until the user runs the code based on the flow you want to debug through key F6 (go to the next line of code), F7 (go inside the function) or F8 (go to the next break point or if there are no more break points to run the code).
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You can select a variable or function whose value you want to see.
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You can use the console to check values or check for some changes to the browser itself.