function add_onload(element, new_function) {
	var old_onload = element.onload;

	if (typeof old_onload != 'function') {
		old_onload = function(){};
	}

	element.onload = function (){
		old_onload();
		new_function();
	}
}

function add_onunload(element, new_function) {
	var old_onunload = element.onunload;

	if (typeof old_onunload != 'function') {
		old_onunload = function(){};
	}

	element.onunload = function (){
		old_onunload();
		new_function();
	}
}

function add_onfocus(element, new_function) {
	var old_onfocus = element.onfocus;

	if (typeof old_onfocus != 'function') {
		old_onfocus = function(){};
	}

	element.onfocus = function (){
		old_onfocus();
		new_function();
	}
}