How to allow alphanumeric in txtbox using javascript in.net?

Question

I have one textbox thats allow alphanumeric if user enters symbols show the alert message

'You have enter symbol do you want to continue'

'yes/no

If click yes symbol is allowed.if click no symbol is not allowed.

Ravi Kumar · Answer

Go with regular Expression it might be helpful $( '#text' ).keypress(function (e) { var regex = new RegExp( ^[a-zA-Z0-9]+$ ); var str = String.fromCharCode(!e.charCode ? e.which : e.charCode); if (regex.test(str)) { return true ; } e.preventDefault(); return false ; });