Concise and short JavaScript IE browser judgment code_javascript skills

The world's shortest Javascript method to determine IE browser comes from Russia! It has been tested on various versions of IE and other currently popular browsers. Although Microsoft has been aware of IE-based bugs, it has never corrected them.

Copy code The code is as follows:

The above code running result: return true under IE, other standards The browser returns false. !-[1,], only 6 bytes!
But if you judge the other way around, if the standard browser returns true and IE returns false, you can shorten it by one byte.

Copy code The code is as follows:

After reading this, are you curious about how these work? Please continue reading below.
The reason for this bug is that IE will add an empty array element to the total number of array elements.
[1,]. Length standard browser will return 1 (based on standard ECMAscript, the comma "," at the end of the array will be ignored, this is to facilitate display in a column and automatic generation, etc.), but IE will Return 2. When you print this array IE will return "1, ", which is two elements, while other standard browsers will return "1".
This is easy to verify, such as running the following code in IE and FF:

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[1,] In fact, the browser operation is toString() to convert to a string, -[1,] is to force the string to a number. IE will return NaN, but unfortunately NaN is not a number, because "1," after [1,] is converted into a string, contains a comma. Other standard browsers will return -1, which is a non-zero number.
You know, converting NaN to Boolean type will return false, so -[1,] will return false under IE. Any non-0 number converted to Boolean type (such as -1) will return true under standard browsers. So we get a judgment result, !-[1,] returns true under IE, but returns false under other standard browsers. This also achieves the purpose of distinguishing and judging IE browsers.
Of course, as mentioned before, Microsoft has actually known about this bug for a long time, but has never fixed it, so in the future, IE8 IE browser is not sure whether it will still work, but basically IE has not been repaired for so many generations, and it is unlikely that IE will be repaired in the future.
The following are some other codes for distinguishing IE browsers, you can also refer to them:

Copy the code The code is as follows: