<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>jQuery如何判断checkbox（复选框）是否被选中以及全选、反选</title>
<script type="text/javascript" src="https://www.jb51.net/jquery.js"></script>
<script type="text/javascript">
<!--
$("document").ready(function(){
$("#all").click(function(){
if(this.checked){
$("input[name='checkbox']").each(function(){this.checked=true;});
$("#btn1").attr("value","反选");
}else{
$("input[name='checkbox']").each(function(){this.checked=false;});
$("#btn1").attr("value","全选");
}
});
$("#btn1").click(function(){
$("[name='checkbox']").attr("checked",'true');//全选
});
$("#btn2").click(function(){
$("[name='checkbox']").removeAttr("checked");//取消全选
});
$("#btn3").click(function(){
$("[name='checkbox']:even").attr("checked",'true');//选中所有奇数
});
$("#btn4").click(function(){
$("[name='checkbox']").each(function(){
if($(this).attr("checked"))
{
$(this).removeAttr("checked");
}else{
$(this).attr("checked",'true');
}
});
});
$("#btn5").click(function(){
var str="";
//$("input:checkbox[name='checkbox']:checked").each(function(){//可以
$("[name='checkbox'][checked]").each(function(){
str+=$(this).val()+"\r\n";
});
alert(str);
});
});
//-->
</script>
</head>
<body>
<form method="post" action="">
<input type="checkbox">
<input type="button" value="全选">
<input type="button" value="取消全选">
<input type="button" value="选中所有奇数">
<input type="button" value="反选">
<input type="button" value="获得选中的所有值">
<br />
<input type="checkbox" value="checkbox1">checkbox1
<input type="checkbox" value="checkbox2">checkbox2
<input type="checkbox" value="checkbox3">checkbox3
<input type="checkbox" value="checkbox4">checkbox4
<input type="checkbox" value="checkbox5">checkbox5
<input type="checkbox" value="checkbox6">checkbox6
<input type="checkbox" value="checkbox7">checkbox7
<input type="checkbox" value="checkbox8">checkbox8
</form>
</body>
</html>