Check alphanumeric characters in field

Question

I have a validation problem in a text field. I need the field does not allow ALPHANUMERIC characters, this validation has to be done obligatorily with jquery.

Answer 1

You didn’t give much information about jQuery Validate, although you explicitly marked the topic with this tag. But also you have not provided us with any basis for work.

So I have to consider the two possibilities.

Sem jQuery Validate

<input id="field" name="field" />
<button type="button" id="button">OK</button>

$( document ).ready( function() {

    $( '#button' ).click( function( e ) {

        e.preventDefault();

        if( new RegExp( "[a-zA-z0-9]+" ).test( $( '#field' ).val() ) === false ) {
            alert( 'Somente caracteres alfa-numéricos' );
        }
    });
});

Demo

Com jQuery Validate:

<form id="form">
    <input id="field" name="field" />
    <button type="button" id="button">OK</button>
</form>

$( document ).ready( function() {

    $( '#form' ).validate({

        rules: {
            field: { pattern: /[a-zA-Z0-9]+/ }
        }
    });
});

Demo

Just pay attention to the detail of an additional file being included in the second Fiddle. I don’t use jQuery Validate so I don’t know if this version I used is the most updated or not.

Note that the Regular Expression technique the same for both cases, changes only the implementation.