JavaScript to judge integer methods to share _javascript skills

There are two ways to judge integers: regular judgments and literal judgments.

Because the verbatim judgment efficiency is too low, here is not described, interested spectators can own Google.

1. Regular judgment

Copy Code code as follows:

var r =/^\+? [1-9]　　[0-9]*$/; Positive integer
Console.log (R.test (1.23));

Effect test:
http://jsfiddle.net/wzsdp9Lc/

Extended Feature List

Copy Code code as follows:

"^\\d+$"//non-negative Integer (positive integer + 0)
"^[0-9]*[1-9][0-9]*$"//Positive integer
"^ ((-\\d+) | (0+)) $ "//non-positive integer (negative integer + 0)
"^-[0-9]*[1-9][0-9]*$"//Negative integer
"^-?\\d+$"//Integer
"^\\d+ (\\.\\d+)? $"//nonnegative floating-point number (positive float + 0)
"^ ([0-9]+\\. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*)] $ "//Positive floating-point number
"^ ((-\\d+ (\\.\\d+)?) | (0+ (\\.0+)) $ "//non-positive floating-point number (negative floating-point number + 0)
^ (-([0-9]+\\. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*))] $ "//negative floating-point number
"^ (-?\\d+) (\\.\\d+)? $"//floating-point number

2. Rounding Judgment

The idea of this method is to determine whether it equals the original value after rounding

Copy Code code as follows:

var num=1.23;
if (parseint (num)!= num) {
Console.log (num+ "is not an integer");
}
else{
Console.log (num+ "as an integer");
}

Effect test
http://jsfiddle.net/euvn0L1g/1/