jquery学习1
<script type="text/javascript" src="../js/jquery-1.3.1.js"> </script>
<script type="text/javascript">
alert($);
alert(jQuery===$);
</script>
弹出：
1：
function (selector, context) {
return new (jQuery.fn.init)(selector, context);
}

2：true

===================================================
<script type="text/javascript">
var varMap={};
for(var i in window){
varMap[i]=1;
}
</script>
<script type="text/javascript" src="../js/jquery-1.3.1.js"> </script>
<script type="text/javascript">
for(var i in window ){
if(i in varMap) continue;
alert(i);
}
</script>

====================================================
弹出：
1:$
2:jQuery
说明：加入jquery类库后，多了两个全局变量