function clearField()
{
	var fields = document.getElementsByTagName( 'INPUT' );
	for ( var i = 0; i < fields.length; i++ ) {
		if ( fields[i].className.indexOf( 'clear_field' ) != -1 ) {
			fields[i].onfocus = function() {
				if ( this.value.indexOf('mail') != -1 || this.value== zoektekst || this.value == '******' ) {
					this.value = '';
				}
			}
		}
	}

}