var captcha_url = '';
$(document.body).ready(function(){
	$('#change_image').bind('click', function (){
		if (captcha_url == ''){
			captcha_url = $('#captcha').attr('src');
		}
		var tmp_image = new Image();
		tmp_image.src = captcha_url+'&math='+Math.random();
		$(tmp_image).bind('load',function (){
			$('#captcha').attr('src',tmp_image.src);
			$('#captcha_form').focus();
		});
	});
});