css模拟实现selec下拉框_html/css

var $$ = function (id) {
return document.getElementById(id);
}
window.onload = function () {
var btnSelect = $$("btn_select");
var curSelect = btnSelect.getElementsByTagName("span")[0];
var oSelect = btnSelect.getElementsByTagName("select")[0];
var aOption = btnSelect.getElementsByTagName("option");
oSelect.onchange = function () {
var text=oSelect.options[oSelect.selectedIndex].text;
curSelect.innerHTML = text;
}
}