Question

My way: code

<form>
    <input type="text" value="">
    <input type="submit" value="submit"> type a space and press Submit
</form>

$('form').submit(function(){
    if($('input').val() == ' ') {
        alert($('input').val().length);
    }
   return false;    
});

But I’d like to solve this problem using CSS3 selectors like $('input[value*=" "]')

Answer 1

If you are asking to use CSS3 selector through jquery then $(':input[value*=" "]') should do it.

example: http://www.jsfiddle.net/gaby/cruRd/

If you want to create an actual CSS3 rule in your stylesheet then input[value*=' ']{..} will work, but only for values in the actual attribute (in the source code) and not the value as modified inside the browser..

example: http://www.jsfiddle.net/gaby/VzE9T/