JavaScript Text Only Input

This function can be used on the onkeypress event of a HTML input box to only allow entry of text charactes: A-Z, a-z, dash, space, and backspace.


<input type="text" id="name" onkeypress="return textonly(event);" /> 


function textonly(e){
var code;
if (!e) var e = window.event;
if (e.keyCode) code = e.keyCode;
else if (e.which) code = e.which;
var character = String.fromCharCode(code);
//alert('Character was ' + character);
    //if (code == 8) return true;
    var AllowRegex  = /^[\ba-zA-Z\s-]$/;
    if (AllowRegex.test(character)) return true;    
    return false;

Javascript Validate South African Identity Number

function validateSAID(elementID)
var SAIDRegEx = /^(((\d{2}((0[13578]|1[02])(0[1-9]|[12]\d|3[01])|(0[13456789]|1[012])(0[1-9]|[12]\d|30)|02(0[1-9]|1\d|2[0-8])))|([02468][048]|[13579][26])0229))(( |-)(\d{4})( |-)(\d{3})|(\d{7}))/;
if (SAIDRegEx.test(document.getElementById(elementID).value)) return true; return false;

Take a look at this blog post for more information about SA ID number structure and validation.

Javascript key codes

JavaScript Numeric Only Input

Use the following JavaScript function to only allow numeric (0-9) input and backspace input in a web form text field.


function numbersonly(e) {
var unicode=e.charCode? e.charCode : e.keyCode;
if (unicode!=8){ //if the key isn't the backspace key (which we should allow)
if (unicode<48||unicode>57) //if not a number return false //disable key press


<input onkeypress=”return numbersonly(event);” name=”VAT_Number”>

To allow for tabbing change (unicode!=8) to (unicode!=8 && unicode!=9)

Simple Javascript CAPTCHA

Simple CAPTCHA using Javascript. The page collecting the form information should collect from forms only. eg. in ASP: request.forms(“name”)

Click here to download the code: BotBoot1.html

Validate SA Cell Number with Javascript

function validate(){
var MobileNumber = document.getElementById(“MobileNumber”).value;
var MobileNumberRegEx = /^\+27[78][23467][0-9]{7}/;
if (MobileNumberRegEx.test(MobileNumber)) {
return true;
alert(“Please enter a valid South African mobile phone number\nin the following format: +27820000000”);
return false;