Enabling disabled submit button doesn't work during filling the field which is required to enable the submit
===

sorry if the title isn't clear, i was trying to explain in the best possible way. The situation I have is the following: I have a newsletter with a submit button. I have used jquery to unlock the SUBMIT button after the correct email is typed in. It is working fine apart of one thing - I have to click anywhere outside the field (not on the submit button) to enable the submit, then on submit. There was something I have to add somewhere around this line i think, but I dont know what:

    document.getElementById("btnSubmit").disabled = false;

the full code is here:

HTML:

    <div class="element">
        <input type="text" id="email" name="email" value="Enter your email" />
    </div>           
    
	<div id="submit">
		<input name="submit" id="submit" src="_images/generic/send_button.png?submit+button=" type="image" disabled="disabled" />
	</div>

and jq:

    $.fn.swapText = function(){
	return this.each(function(){
		var tmpDefVal = $(this).val();
		$(this).css('color', '#999');
		
		$(this).focus(function(){
			if($(this).val() == tmpDefVal){
				$(this)
					.css('color', '#000')
					.val('');
			}
		});
		
		$(this).blur(function(){
			if($(this).val() == ''){
				$(this)
					.css('color', '#999')
					.val(tmpDefVal);
			}
		});
	
	});
}

$(document).ready(function(){

	$('#email').swapText();
	
	$('#email').change(function(){
		var regexp = /^\w+[@]\w+\.\w{2}$/;
		
		if(regexp.test($(this).val())){
			$(this).removeClass('err');
			$(this).addClass('ok');
			document.getElementById("submit").disabled = false;
		}else{
			$(this).removeClass('ok');
			$(this).addClass('err');
		}
	});
	
});


Thanks for any help.