// add focus and blur handlers to all text fields with placeholder text
function add_input_focus(input_class) {
	var input_fields = document.getElementsByTagName('input','textarea');
	for (f=0; f<input_fields.length; f++) {
		if (input_fields[f].className.search(input_class) != -1) { // search() returns the index of the regEx, or -1 if not found
			input_fields[f].onfocus = function() {
				if (this.className.search(input_class) != -1) {
					var classes = this.className;
					var start_index = classes.search(input_class);
					var string_length = input_class.length;
					this.className = classes.substring(0,start_index) + classes.substring(start_index + string_length);
					this.value = '';
				}
			};
		}
	}
}