function getObject(objectId) {
    if(document.getElementById && document.getElementById(objectId)) {
	// W3C DOM
	return document.getElementById(objectId);
    } else if (document.all && document.all(objectId)) {
	// MSIE 4 DOM
	return document.all(objectId);
    } else if (document.layers && document.layers[objectId]) {
	// NN 4 DOM.. note: this won't find nested layers
	return document.layers[objectId];
    } else {
	return false;
    }
}
//创建xmlhttp。此写法兼容firefox2,firefox3和ie。    
function createXMLHTTP() {
	var xmlhttp = null;
	if(window.ActiveXObject) {
		try {xmlhttp=new ActiveXObject("Msxml2.XMLHTTP");}
		catch(e){try{xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");}
		catch(e){}}
	} else if(window.XMLHttpRequest) {
		xmlhttp = new XMLHttpRequest();
		if(xmlhttp.overrideMimeType) {
			xmlhttp.overrideMimeType('text/xml');
		}
	} else {alert("Create XMLHttpRequest object false!");return false;} 
    return xmlhttp;
}
function $(id){
	if(document.getElementById && document.getElementById(id)) {
	// W3C DOM
	return document.getElementById(id);
    } else if (document.all && document.all(id)) {
	// MSIE 4 DOM
	return document.all(id);
    } else if (document.layers && document.layers[id]) {
	// NN 4 DOM.. note: this won't find nested layers
	return document.layers[id];
    } else {
	return false;
    }
}
//根据自定义的allownull属性来判断表单中不允许为空的属性有哪些为空
function allowNull(formObj) {
	var len = formObj.elements.length;
	for(var i = 0;i < len;i++) {
		var el = formObj.elements[i];
		if(el.getAttribute("allownull")!=null && el.getAttribute("allownull")=='false') {
			if(el.value==null || el.value=='') {
				alert('请填写必填项内容！');
				el.focus();
				return false;
			}
		}
	}
	return true;
}
function addFavorite(sURL, sTitle){
	try{
		window.external.addFavorite(sURL, sTitle);
	}catch (e){
		try{
			window.sidebar.addPanel(sTitle, sURL, "");
		}catch (e) {
			alert("加入收藏失败，请使用Ctrl+D进行添加");
		}
	}
}
//textarea 输入字数限制
function textCounter(field, countfield, maxlimit) {

    	var textarea = document.getElementById(field);
    	var counter = document.getElementById(countfield);
		if (textarea.value.length > maxlimit) textarea.value = textarea.value.substring(0, maxlimit);
		else counter.innerHTML = maxlimit - textarea.value.length;
	}
	
function searchWord() {
	if(document.searchform.k.value==''){
		alert('请输入关键词');
		document.searchform.k.focus();
		return false;
	}else{
		var word = document.searchform.k.value;
		var id;
		for (i=0;i<document.searchform.searchradio.length;i++) {
			if (document.searchform.searchradio[i].checked) {
				id = document.searchform.searchradio[i].value;
				break;
			}
		}
		if("insite"==id){
			document.searchform.action="";
			document.searchform.target="_parent";
			document.searchform.method="get";
		}else{
			word = escape(word);
			document.searchform.action="http://so.1680.ws/s?word="+word;
			document.searchform.method="post";
			document.searchform.target="_blank";
		}
		document.forms["searchform"].submit();
	}
}
var agt=navigator.userAgent.toLowerCase();
var is_ie=(agt.indexOf("msie")!=-1 && document.all);
//if(top.location!= self.location){top.location = self.location;}