1 text 操作

function textOpration() {
var txt = document.getElementById("txtTest");
txt.value = txt.value + ":welcome!" ;
}
2 lable 操作

function lbOpration() {
document.getElementById("mylbText").innerHTML = ":welcome!";
}
3 select 操作
//单select 取值
function showMsg() {
var sel = document.getElementById("myselect");
var str = "";
for (i = 0; i < sel.length; i++) {
if (sel.options[i].selected) {
str += sel.options[i].text + "<br/>";
}
}
document.getElementById("lbTest").innerHTML = str;