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JavaScript type conversion (character to number, number to character)_javascript skills

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Release: 2016-05-16 18:20:28
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In Java, the forced conversion between basic types is not like this. For example, to convert an integer into a string, you must use the Integer.toString() static method or the String.valueOf() static method to convert the string into an integer. Integer.valueOf() must be used.
It can be seen that type conversion in JavaScript cannot be regarded as "forced type conversion".
In JavaScript, Double and Int types are regarded as Number objects, so whether it is typeof 1 or typeof 1.0, number is returned. In this way, we don't have to worry about whether it is an Int or Double type, and let the JavaScript interpretation engine handle it internally.

If you want to convert Number to String, you can use Number's toString() method, (like (1).toString() brackets are required or 1.toString() spaces are required, otherwise a compilation error will occur. If Variables are not required), or call the String() function. Both methods will automatically call NumberToString() inside the interpretation engine, or call other functions based on the base, which are basically similar.
If you want to convert String to Number, you can use the Number() function. It will automatically determine whether the String is an integer or a floating point number, and then use the corresponding data type internally. In addition, you can use the global functions parseInt() and parseFloat() , they convert according to your requirements. Similarly, they use internal functions such as StringToNumber, StringToInt, etc. to explain the internal mechanism of the engine.
If Double is converted to Int, Math.floor() function (truncation) or Math.round() (rounding) must be used.
Int is converted to Double. There is no need to consider any problems. Just convert Int directly. Operate as Double
Note: Number and String functions are special functions. In the JS engine, they will automatically determine whether to call as a constructor or a normal call, so you can use the new keyword or call it directly as a function. .
Regarding JS reference manual , Microsoft has a very good CHM, which has guides and API references. It is Windows scripting technology, Chinese version, I downloaded it from MSDN. Regarding the JS interpretation engine, I refer to Netscape's Spidermonkey, which is now maintained by the Mozilla organization.

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