How to debug javascript

How to debug JavaScript: 1. Use the [console.log()] method to print the JavaScript value on the debugging window; 2. Use the debugger keyword to stop executing JavaScript and call the debugging function.

The operating environment of this tutorial: Windows 7 system, JavaScript version 1.8.5, DELL G3 computer.

Methods for debugging javascript:

1. console.log() method

If the browser supports debugging, you You can use the console.log() method to print JavaScript values ​​on the debug window:

Instance

a = 5;
b = 6;
c = a + b;
console.log(c);

2, debugger keyword

debugger keyword Used to stop executing JavaScript and call debugging functions.

This keyword has the same effect as setting a breakpoint in the debugging tool.

The debugger statement will not work if no debugging is available.

Enable debugger and the code stops executing before the third line.

Example

var x = 15 * 5;
debugger;
document.getElementbyId("demo").innerHTML = x;

Related free learning recommendations: javascript learning tutorial

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