function check_form() {
		pattern = /^([a-zA-Z0-9_-])+([\.a-zA-Z0-9_-])*@([a-zA-Z0-9_-])+(\.[a-zA-Z0-9]+)+$/;
		if( !pattern.test( $('#sender_email').val() ) ) {
			alert( 'Please enter a valid email address.' );
			return false;
		}
		else if( $('#subject').val() == '' ) {
			alert( 'Please enter a subject for your message.' );
			return false;
		}
		else if( $('#body').val() == '' ) {
			alert( 'Please enter a message.' );
			return false;
		}
          else {
               var vars = $('#contact_form').serialize();
               $('#contact_form').slideUp();
               $.ajax( {                    
                    type : "GET",
                    cache:false,
                    url: "index.php",
                    data: vars,
                    success:function( response ) {
                         $('#response').html( response );
                    }
               } );
               return false;
          }
}