if (i%4 ==0 ) 逻辑的魅力 在于 这里

<div class="course_height">

</div>
<script src="js/jquery.min.js"></script>
<script>
var i=0;
var s1 = "<ul class='intelliGence'>";
var s3 = "</ul>";
var shtml = "";
for(i=0;i<20;i++){
var s2='<li>'+i+'</li>';
if(i%4 == 0){
shtml += s1;
}
shtml += s2;
if((i+1)%4 == 0){
shtml += s3;
}
}
shtml += s3;
var recbody = $(".course_height");
recbody.text("");
recbody.append(shtml);
</script>