1，js限制checkbbox勾选个数的代码：
<!DOCTYPE HTML <span PUBLIC</span> "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>限制复选框选择的数量-www.jbxue.com-脚本学堂</title>
<script type="text/javascript" >
<span function</span> <span checkDate</span><span (n){
</span><span var</span> checkedCount=0<span ;
</span><span for</span>(<span var</span> i=0;i<myForm.course.length ;i ++<span ){
</span><span if</span>(myForm.course[i].<span checked){
checkedCount</span>++<span ;
}
}
</span><span if</span>(checkedCount><span n){
alert(</span>"不能选超过三门课程"<span );
</span><span return</span> <span false</span><span ;
}
}
</span></script>
</head>
<body>
<form name="myForm" method="post" id="myForm" action="test.php"><span
请选择这学期的选课(最多三门)：</span><br>
<input type="checkbox" name="course[]" value="语文" onClick="return checkDate(3)">语文<br>
<input type="checkbox" name="course[]" value="数学" onClick="return checkDate(3)">数学<br>
<input type="checkbox" name="course[]" value="英语" onClick="return checkDate(3)">英语<br>
<input type="checkbox" name="course[]" value="化学" onClick="return checkDate(3)">化学<br>
<input type="checkbox" name="course[]" value="物理" onClick="return checkDate(3)">物理<br>
<input type="checkbox" name="course[]" value="政治" onClick="return checkDate(3)">政治<br>
<input type="submit" value="提交">
<input type="reset" value="取消">
</form>
</body>
</html>
<?<span php
</span><span /*</span><span *
* 获取checkbox的值
* edit by www.jbxue.com
</span><span */</span>
<span $course</span>=<span $_POST</span>['course'<span ];
</span><span for</span>(<span $i</span>=0;<span $i</span><<span count</span>(<span $course</span>);<span $i</span>++<span )
{
</span><span if</span>(<span $course</span>[<span $i</span>]!=""<span )
{
</span><span echo</span> <span $course</span>[<span $i</span>]."<br/>"<span ;
}
}
</span>?>
