function nav(obj){
	var nd = document.getElementById('nav').getElementsByTagName('DD');
	var nt = document.getElementById('nav').getElementsByTagName('DT');
	for( var i = 0; i < nd.length; i++ ){
		nd[i].style.display='none';
	}
	for( var i = 0; i < nt.length; i++ ){
		nt[i].style.background='none';
	}
	var p = obj.getElementsByTagName('DD');
	obj.getElementsByTagName('DT')[0].style.background = '#CCC';
	for( var i = 0; i < p.length; i++ ){
        p[i].style.display="block";
    }
}

function menuFix(){
    var sfEls = document.getElementById('nav').getElementsByTagName('li');
    for(var i=0; i<sfEls.length; i++){
        sfEls[i].onmouseover=function(){
            this.className+=(this.className.length>0? ' ': '') + 'sfhover';
        }
        sfEls[i].onmouseout=function(){
            this.className=this.className.replace(new RegExp("( ?|^)sfhover\\b"),'');
        }
    }
}

function blurkey(){
    var key = document.getElementById('key');
    if(key.value == ''){
        key.style.color = '#aaa';
        key.value = '产品搜索..';
    }
};

function focuskey(){
    var key = document.getElementById('key');
    key.style.color = '#000';
    if(key.value == '产品搜索..') key.value = '';
};

function checkkey(){
	var a = document.getElementById('key');
	if(a.value == '' || a.value == '产品搜索..'){
		alert("请输入您想查找的商品名称");
		a.value = '';
		a.focus();
	 	return false;
	}
}