limiting character in textbox

Question

I have textbox to enter only alphabet and numerical values. I do not want use plugin. Is it possible'

Answer 1

$(":text").keyup(function() {
    if (this.value.match(/[^a-zA-Z0-9]/)) {
        this.value = this.value.replace(/[^a-zA-Z0-9]/g, '');
    }
});

Answer 2

Check this... Sweet Validation