网页下拉列表实现多选

今天在做一个网页的时候需要完成下拉的时候选择多个，刚开始打算用原生javascript代码实现，后来发现有点困难，网上查了下可以用jquery的插件实现后来还是自己结合jquery实现了上述效果！

1、先看看效果

2.代码实现

2.1 静态页面部分

<body>
<ul class="main_ul">
<li class="main_li">
<a id="main_a">
<input id="smsType_txt" readonly="true" type="text"/>
</a>
<ul class="child_ul">
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>内部短信</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>公共信息</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>欠税提醒</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>资料催报</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>内部短信</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>公共信息</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>欠税提醒</span>
</li>
<li class="child_li">
<input type="checkbox" class="sms_checkBox"><span>资料催报</span>
</li>
</ul>
</li>
</ul>
</body>

2.2 js 代码

$(document).ready(function(){
$("#main_a").click(function(event){
event.stopPropagation();
$(".child_ul").slideToggle(200);
});
$(document).click(function(){
$(".child_ul").slideUp(200);
});
$(".child_li").click(function(event){
event.stopPropagation();
if($(this).children("input").attr("checked")) {
$(this).children("input").attr("checked",false);
}else {
$(this).children("input").attr("checked",true);
}
hostCheckBoxValues();
});

function hostCheckBoxValues() {
var span_elms = $(".child_li :checkbox[checked]").next("span");
var size = $(".child_li :checkbox[checked]").next("span").size();
var sms_Str = "";
for(var i = 0; i < size; i++) {
var appendStr = i == (size-1)? span_elms[i].innerHTML : span_elms[i].innerHTML + ",";
sms_Str += appendStr;
}
$("#smsType_txt").val(sms_Str);
}
});

}

/*
获取参数
*/
function getParameters() {
var url=decodeURI(window.location.href);
var pos = url.lastIndexOf("?");
var pars = '';
if(pos>=0){
pars = url.substring(pos+1);
}
var args = pars.split("&");
var result = {};
for(var i=0;i<args.length;i++) {
var arr = args[i].split('=');
if(arr.length==2){result[arr[0]] = arr[1]};
}
return result;
}

/**
*
* @param title
* @param type
* @param timeOut
*/
/
function openAlertWindow(title,type,timeOut) {
if(type == 1) {
$("#alert_img").attr("src","../res/wifi/images/loading.gif");
$("#alert_span").html("正在加载");
}else if(type == 2) {
$("#alert_img").attr("src","../res/wifi/images/gou.png");
$("#alert_span").html("成 功");
}else if(type == 3){
$("#alert_img").attr("src","../res/wifi/images/error.png");
$("#alert_span").html("系统错误");
}
$("#alert_div").fadeIn(500);
if(type == 2 || type == 3) {
setTimeout(function(){
$("#alert_div").fadeOut(500);
},timeOut);
}
}

function closeAlertWindow(timeOut) {
$("#alert_div").hide(500);
}

function loadAlertDivTag() {
$("body").append('<div style=" 100px;height: 50px;background-color: green">ssss</div>');
}