实习生，想问一下关于那个鼠标事件，当鼠标经过一区域的时候显示一个div框，然后鼠标移走时div框消失........怎么写？...还有这段代码什么意思，这个是关于百度地图开发的代码
jQuery(document).ready(function(){
var buildinfo;
var jg;
var x = [];
var y = [];
var length;
var pointarray;
jQuery.getJSON("json/buildinginfo4x.json", function(data){
//======设置全局变量JsonData_Building=======
//数据需要在Cmap_Base中的mouseove事件中使用，判断在哪个层作画，是/否隐藏该层
//JsonData_Building = data;
//=================================
var iitmp = 0;
var oldpertmp;
document.getElementById("d_map").onclick = function(){
//alert(CZoomControl_zoomPercent[CZoomControl_zoomIndex]+""+Base_OldPercentTmp);
if (isInsidePolygon(_Theodolite$point.x, _Theodolite$point.y, pointtmp, 0.8, CZoomControl_zoomPercent[CZoomControl_zoomIndex])) {
//JqueryMarker$strMsg(data.building[iitmp].title);//弹出消息
var div_3d = document.createElement("Div");
div_3d.id = "div_showbuildinfo";
//str = "<iframe src='flash/Test11_mv.html' width='800' height='500' frameborder='no' border='0' marginwidth='0' marginheight='0' scrolling='no'></iframe>";
str = "<iframe src='divin/test09_newflat.html' width='775' height='559' frameborder='no' border='0' marginwidth='0' marginheight='0' scrolling='no'></iframe>";
str += "<div width='755px' class='span_repair a_close' style='cursor:pointer;'><center><a href='#' class='span_repair a_close'>关闭</a></center></div>";
div_3d.innerHTML = str;
$("d_map").appendChild(div_3d);
a=hiBox('#div_showbuildinfo', data.building[iitmp].title, '1200', '620', '', '.a_close');
//alert(a);
}
}
var flag = false;
var pointtmp = [];
document.getElementById("d_map").onmousemove = function(){
//if(CZoomControl_zoomPercent[CZoomControl_zoomIndex]==0.8) Base_OldPercentTmp=0.8;//同步高亮显示区
for (var ii = 0; ii < data.building.length; ii++) {
pointtmp = data.building[ii].point;
if (document.getElementById("div_cityinfomapper").childNodes.length >= 1 && flag) {
iitmp = 0;
flag = true;
return;
}
if (isInsidePolygon(_Theodolite$point.x, _Theodolite$point.y, pointtmp, 0.8, CZoomControl_zoomPercent[CZoomControl_zoomIndex]))//鼠标焦点在高亮显示区
{
// alert(true);
iitmp = ii;
//创建用于画图的div节点
if (document.getElementById("div_building_" + data.building[ii].bid) == null) {