Regex for different classname form input - regex

Question

This is the original code
$('.holder').on('keypress', 'alphabet', function (e) {
if (window.event) code = e.keyCode;
else code = e.which;
var myRegExp = new RegeExp(/[A-Z]/i);
if (myRegExp.test(String.fromCharCode(code))) {
return true;
} else return false;
});
however i want to make this code reusable as classname as parameter, like this one, but its not working :
$('.holder').on('keypress', classname, function (e) {
if (window.event) code = e.keyCode;
else code = e.which;
var pattern;
if (classname == "alphabet") pattern = /[A-Z]/i;
else if (classname == "number") pattern = /[0-9]/;
var myRegExp = new RegeExp(pattern);
if (myRegExp.test(String.fromCharCode(code))) {
return true;
} else return false;
});
see this FIDDLE

Answer 1

This should be your HTML. You should have a name attribute for an input element
<div class="holder">
alphabets only : <input type="text" name="name" class="alphabet" /><br />
numbers only : <input type="text" name="age" class="number" />
</div>
And this is the JavaScript. You need an event on input and not on holder and you don't need to pass classname as a parameter; rather check it with .attr('class')
$('input').on('keypress', function (e) {
if (window.event) code = e.keyCode;
else code = e.which;
var pattern;
if ($(this).attr('class') == "alphabet") pattern = /[A-Z]/i;
else if ($(this).attr('class') == "number") pattern = /[0-9]/;
var myRegExp = new RegExp(pattern);
if (myRegExp.test(String.fromCharCode(code))) {
return true;
} else return false;
});
Demo

Answer 2

on(...) does not define a function. It calls a function. You can't have an undefined variable there. Wrap the whole thing into a function.
Also, the second parameter to on(...) needs to be a selector, but "alphabet" would try to select a tag <alphabet>, which does not exist. The class selector is ".alphabet".
You also misspelled RegExp.
function applyKeypressValidation(selector, classname) {
$('.holder').on('keypress', selector, function (e) {
if (window.event) code = e.keyCode;
else code = e.which;
var pattern;
if (classname == "alphabet") pattern = /[A-Z]/i;
else if (classname == "number") pattern = /[0-9]/;
var myRegExp = new RegExp(pattern);
if (myRegExp.test(String.fromCharCode(code))) {
return true;
} else return false;
});
}
applyKeypressValidation('.alphabet', 'alphabet');
applyKeypressValidation('.number', 'number');