JS Regular expression verifies that input is a digital regular validator

This article provides several examples of commonly used JS regular expression number of instance expression functions below to see.

is the number 0-9

function Isalphanumber (str)
{
var result=str.match (/^[a-za-z0-9]+$/);
if (result==null) return false;
return true;
}

is a number

function Isnumber (str)
{
return!isnan (str);
}

is an integral type

function Isint (str)
{
var result=str.match (/^ (-|+)? d+$/);
if (result==null) return false;
return true;
}

is a regular expression of numbers

function Regisdigit (fdata)
{
var reg = new RegExp ("^[0-9]$");
Return (Reg.test (fdata));
}