Summary of basic js usage

This time I will bring you a summary of the basic use of js. What are the precautions for the basic use of js. The following is a practical case, let’s take a look.

0/0 ==> NaN(Not a Number)
You can use isNaN() to detect whether the value is NaN

Escape character

var a = 'king\'s'alert (a);
alert(null == undifined) //truealert(null === undifined) //false 数据值相等 类不相等

' single Quotation marks
\n Carriage return and line feed
\r Line feed
\t Horizontal tab character

Variable parameters

function sum(){    var paramsNum = arguments.length; //将parameters的个数传入variable
    var sum = 0;    for(var i=0; i <paramsNum; i++)
    {
      sum += argument[i];
    }  return sum;
}

I believe you read this article You have mastered the case method. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Recommended reading:

The use of Polyfill annotations and preventing modifications in JS

JS object inheritanceUse cases Detailed explanation

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