JS to determine whether it is a number, whether it is an integer, whether it is a floating point

1, JS judge whether it is a number, whether it is an integer, whether it is a floating point

Regular Expression methods

function checkrate (input)
{
var re =/^[0-9]+.?   [0-9]*$/; Determines whether a string is a number//positive integer/^[1-9]+[0-9]*]*$/
if (!re.test (Input.rate.value))
{
Alert ("Please enter a number (example: 0.02)");
Input.rate.focus ();
return false;
}
}

The following is a common function notation

function Baseisnotnum (thenum)
{
Determine whether a number
if (Basetrim (thenum) = = "")
return true;
for (Var i=0;i<thenum.length;i++) {
Onenum=thenum.substring (i,i+1);
if (onenum< "0" | | onenum> "9")
return true;
}
return false;
}

function Baseisnotint (Theint)
{
Determines whether an integer
Theint=basetrim (Theint);
if ((theint.length>1 && theint.substring (0,1) = = "0") | | Baseisnotnum (Theint)) {
return true;
}
return false;
}

function Baseisnotfloat (thefloat)
{
Determine whether a floating-point number
Len=thefloat.length;
dotnum=0;
if (len==0)
return true;
for (Var i=0;i<len;i++) {
Onenum=thefloat.substring (i,i+1);
if (onenum== ".")
dotnum++;
if ((onenum< "0" | | onenum> "9") && onenum!= ".") | | DOTNUM>1)
return true;
}
if (len>1 && thefloat.substring (0,1) = = "0") {
if (thefloat.substring)! = ".")
return true;
}
return false;

IsNaN function
IsNaN (expression:object): Boolean

Evaluates the parameter and returns True if the value is NaN (not a number). This function can be used to check whether a mathematical expression was successfully evaluated as a number.

Availability: Flash Player 5;actionscript 1.0

Parameters
Expression:object-The Boolean value, variable, or other expression to be evaluated.

Return
Boolean-A Boolean value.

Example:

if (IsNaN (Document.login.imgcode.value)) {
Alert (' Verification code must be a number! ‘)
Document.login.imgcode.focus ();
return false;
}

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Reprinted from http://java-admin.iteye.com/blog/507963, thanks to java-admin for sharing.

JS to determine whether it is a number, whether it is an integer, whether it is a floating point