Some magical functions of the plus sign ( ) operator in javascript_javascript tips

Javascript is a magical language, and there is a magical plus operator in this magical language.

We can use commonly used addition operators:

1. Addition operation, for example: alert(1 2); ==>3
2. String concatenation, for example: alert(“a” ”b”);==>”ab”

The more advanced one is "=", which also performs the above two operations.

I asked a question yesterday in the javascript jungle group: How to convert the date format string "2000-09-11 19:22" into milliseconds?

Mengzhanren answered me immediately every day: new Date('2000-09-11 19:22′). I tried it but it didn’t work. The correct one should be new Date('2000/09/11 19:22′).

The answer seems to be unimportant. You see there is an plus operator in front of it. To be honest, I have never seen this way of writing before. The magical plus operator in JavaScript also has a very magical effect in converting data types, usually between strings and numerical values. For example, the example given by JavaScript Jungle netizen Jason:

Copy code The code is as follows:

// Hexadecimal conversion:
”0xFF ";                                                                                         // -> 255

// Get the current timestamp, equivalent to `new Date().getTime()`:
new Date();

// More secure parsing of strings than parseFloat()/parseInt()
parseInt(“1,000″); // -> 1, not 1000
”1,000″; NaN, much better for testing user input
parseInt(“010″); // -> 8, because of the octal literal prefix
”010″; // -> 10, `Number()` doesn't parse octal literals
//Some simple abbreviations such as: if (someVar === null) {someVar = 0};
null; // -> 0;

//Convert Boolean type to integer type
true;
//Others:

”1e10″;                                                                -> -12 :

Of course, you can convert numbers into strings by adding numbers to empty strings, for example: alert( typeof (1 ””)); // ->string;

In addition, a subtraction operator is included to convert a string into a number, for example: alert( typeof (“123″-0));//->number;

Of course, there may be some unknown usage features of the plus operator, please leave a message to add!