JavaScript@ Validation Functions

1- Empty Field Validation:- (To check whether a text field is empty or not)

function IsEmpty(aTextField) {
if ((aTextField.value.length==0)
(aTextField.value==null)) {
return true;
}
else { return false; }
}
////////////////////////////////////////////////

2- Numeric Validation:- (To check whether a text field contains Numeric Values)

function IsNumeric(sText)
{
var ValidChars = "0123456789.";
var IsNumber=true;
var Char;


for (i = 0; i < sText.length && IsNumber == true; i++)
{
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1)
{
IsNumber = false;
}
}
return IsNumber;

}
////////////////////////////////////////////////

3- Aplphabet Validation:- (To check whether a text field contains Alphabetic Values)

function IsAlphabet(sText)
{
var ValidChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
var IsAlpha=true;
var Char;


for (i = 0; i < sText.length && IsAlpha == true; i++)
{
Char = sText.charAt(i);
if (ValidChars.indexOf(Char) == -1)
{
IsAlpha= false;
}
}
return IsAlpha;

}
/////////////////////////////////////////////////////////////////////////

3- Email Address Validation:- (To check whether a text field contains valid email value)

function isValidEmail(str) {
return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);

}