JS获取dom 对象 ajax操作 读写cookie函数

var LF = {}; 
LF.version = '1.0.0'; 
//全局函数 
function $(objName) { 
return document.getElementById(objName); 
} 
function $name(objName) { 
return document.getElementsByName(objName); 
} 
function $tag(objName) { 
return document.getElementsByTagName(objName); 
} //广告swf　 flashWrite('SW/2009/HomeGroBuy.swf','950','70','navigation', '##ffffff', 'menuNum=0', 'transparent'); 
function flashWrite(url,w,h,id,bg,vars,win){ 
var flashStr= 
"<div align=\"center\"><object classid='clsid:d27cdb6e-ae6d-11cf-96b8-444553540000' codebase='http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0' width='"+w+"' height='"+h+"' id='"+id+"' align='middle'>"+ 
"<param name='allowScriptAccess' value='always' />"+ 
"<param name='movie' value='"+url+"' />"+ 
"<param name='FlashVars' value='"+vars+"' />"+ 
"<param name='wmode' value='"+win+"' />"+ 
"<param name='menu' value='false' />"+ 
"<param name='quality' value='high' />"+ 
"<param name='bgcolor' value='"+bg+"' />"+ 
"<embed src='"+url+"' FlashVars='"+vars+"' wmode='"+win+"' menu='false' quality='high' bgcolor='"+bg+"' width='"+w+"' height='"+h+"' name='"+id+"' align='middle' allowScriptAccess='always' type='application/x-shockwave-flash' pluginspage='http://www.macromedia.com/go/getflashplayer' />"+ 
"</object></div>"; 
document.write(flashStr); 
} 
//广告图片 imgWrite('images/pic04.jpg', '780', '90', 'http://www.lfang.com/wzzt/2009/lgzt/'); 
function imgWrite(url,w,h,linkUrl){ 
var flashStr= ""; 
if (linkUrl=="") 
flashStr="<img src=\""+url+"\" border=\"0\" width=\""+w+"\" height=\""+h+"\"/>"; 
else 
flashStr="<a href=\""+linkUrl+"\">"+"<img src=\""+url+"\" border=\"0\" width=\""+w+"\" height=\""+h+"\"/>"+"</a>"; 
document.write(flashStr); 
} 
//AJAX操作 
LF.ajax={ 
getXmlhttp : function() { 
var http_request; 
if(window.XMLHttpRequest) { 
http_request = new XMLHttpRequest(); 
if (http_request.overrideMimeType) { 
http_request.overrideMimeType("text/xml"); 
} 
} 
else if (window.ActiveXObject) { 
try { 
http_request = new ActiveXObject("Msxml2.XMLHTTP"); 
} catch (e) { 
try { 
http_request = new ActiveXObject("Microsoft.XMLHTTP"); 
} catch (e) {} 
} 
} 
if (!http_request) { 
window.alert("can't create XMLHttpRequest object."); 
return null; 
} 
return http_request; 
}, 
loadAJAXTab : function (url){// 一般是DIV 
try { 
var xhttp=LF.ajax.getXmlhttp(); 
xhttp.open("GET",url,false); 
xhttp.send(null); 
if (xhttp.readyState == 0)return "0初始化中......"; 
if (xhttp.readyState == 1)return "1初始化中......"; 
if (xhttp.readyState == 2)return "2初始化中......"; 
if (xhttp.readyState == 3)return "3初始化中......"; 
if(xhttp.readyState == 4 && (xhttp.status==200)){ 
var resText=xhttp.responseText; 
if (resText!="")return resText; 
} 
}catch (e) { 
return e; 
} 
}, 
dataSubmit:function(url,urlParameter,method){ //ajax post提交数据 
try{ 
if(method==""){method="POST";} 
var xhttp=LF.ajax.getXmlhttp(); 
xhttp.open(method, url+urlParameter, false); 
xhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
xhttp.send(null); 
if (xhttp.readyState == 0)return "0初始化中......"; 
if (xhttp.readyState == 1)return "1初始化中......"; 
if (xhttp.readyState == 2)return "2初始化中......"; 
if (xhttp.readyState == 3)return "3初始化中......"; 
if (xhttp.readyState == 4 && xhttp.status == 200)return xhttp.responseText; 
}catch(e){ 
return e; 
} 
} 
}; 
//工具 
LF.util = { 
setCookie:function (name,value){//写cookies 
var Days = 30; 
var exp = new Date(); 
exp.setTime(exp.getTime() + Days*24*60*60*1000); 
document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString(); 
}, 
getCookie:function (name){//读取cookies 
var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)"); 
if(arr=document.cookie.match(reg)) return unescape(arr[2]); 
else return null; 
}, 
delCookie:function (name){//删除cookies 
var exp = new Date(); 
exp.setTime(exp.getTime() - 1); 
var cval=getCookie(name); 
if(cval!=null) document.cookie= name + "="+cval+";expires="+exp.toGMTString(); 
}, 
escape:function (html) {//过滤html 
html = html.replace(/&/g, "&"); 
html = html.replace(/</g, "<"); 
html = html.replace(/>/g, ">"); 
html = html.replace(/\xA0/g, " "); 
html = html.replace(/\x20/g, " "); 
return html; 
} 
};