A simple way for javaScript to judge whether a string is a number _javascript tips

Copy Code code as follows:

parseint ("Hello");//return NAN
parseint ("//return"); 110

So the simple way to judge whether a string is a number is to take advantage of isNaN (), and if true, the string is not a number, otherwise it is a number

Copy Code code as follows:

isNaN (parseint ("Hello"));//true;
isNaN ("parseint");//false;

Note: The following methods cannot be used to determine:

Copy Code code as follows:

parseint ("Hello", ten) ==nan;//return false
parseint ("==nan;//return") false

Because Nan and itself do not want to wait, this is more special, the way to Judge Nan is to use isNaN ();