Understanding boolean types in javascript

Speaking of the Boolean type, I believe anyone who has had programming experience knows what it is. But the Boolean type in Javascript is very interesting.

　First of all, it is used to determine whether it is true or false, not just true or false. , it seems that any object can be used as a Boolean judgment. Do you have a sense of accomplishment that "everything in the world is for my use"? I checked it online and copied it from elsewhere and summarized it as follows:

　1. All objects are considered is true.

　2. A string is considered false if and only if it is empty ("" or '').

　3. Null and undefined are considered false.

　4. A number is false if and only if it is 0.

　So it is very convenient to use. If you want to judge whether there is an object on the page, just use this sentence:

if(button)
{
　alert("exist");
}
else
{
　alert("ＳＯＲＲ＼, does not exist");
}

Isn't it very convenient? Using this well can reduce a lot of code for judgment in javascript.

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