Brief explanation of the difference between = = (equal) and = = = (all equal) in Javascript_Basic knowledge

What is the difference between = = (equal) and = = = (all equal) in Javascript?

Let’s look at two examples first:

var n='100' ；

if(n==100)

 { 

alert('equal to');

}

else

                                        

alert('not equal to');

}

The result is "equal to";

When judging whether strings are the same,

var n=false;

if(n=='false')

                                                                              

alert('equal to');

         }

else

                                                             

alert('not equal to');

}

The result is "not equal to".

Reason: === When judging whether two values ​​are the same, it will first judge whether the data type is consistent. If the data type is consistent, it will continue to judge whether the content is the same. == When judging, the data type will be ignored and the judgment will be made directly. The content switch uses full equal judgment

In js, undefined and null are equal if == is used, and unequal if === is used.