Allowing only Alphanumeric values [duplicate]

Answer 1

A digit in the range 1-9 followed by zero or more other digits:

^[1-9]\d*$

Ensure that a string only contains (ASCII) alphanumeric characters, underscores and spaces

^[\w ]+$

Only Alphabets no space or _

^[a-zA-Z]+$

To match a string that contains only those characters (or an empty string), try

^[a-zA-Z0-9_]*$

Some patterns that may help ..but I think you will have to modify them as per your need..I hope it help ..

Answer 2

The better solution might be to go with regular expression based checks. Example below will limit only alphanumeric characters in the field with id text:

$('#text').keypress(function (e) {
    var regex = new RegExp("^[a-zA-Z0-9]+$");
    var str = String.fromCharCode(!e.charCode ? e.which : e.charCode);
    if (regex.test(str)) {
        return true;
    }

    e.preventDefault();
    return false;
});