//方法一
<script language="网页特效">
function checkallbox(box)
{
var f = box.form;
var ischecked = box.checked;
for (var i=0; i<f.elements.length; i++)
{
if (f.elements[i].type.tolowercase() == "checkbox")
{
f.elements[i].checked = ischecked;
}
}
}
</script>
//方法二
<script>
function selectall() {
var checkboxs=document.getelementsbyname("checkboxid");
for (var i=0;i<checkboxs.length;i++) {
var e=checkboxs[i];
e.checked=!e.checked;
}
}
</script>
<a href="#" onclick="selectall()">全选/反选</a>
<form name="checkboxform">
<input type="checkbox" name="checkboxid" id="checkboxid" value="1" />
</form>
//方法三
<script language="javascript">
<!-- begin
var checkflag = "false";
function check(field) {
if (checkflag == "false") {
for (i = 0; i < field.length; i++) {
field[i].checked = true;}
checkflag = "true";
return "false"; }
else {
for (i = 0; i < field.length; i++) {
field[i].checked = false; }
checkflag = "false";
return "true"; }
}
// end -->
</script><body></body>
<form name="form" method="post" action=""><input type="checkbox" name="list" value="1">
<input type="checkbox" name="list" value="2">
<input type="checkbox" name="list" value="3">
<input type=button value="全选" onclick="this.value=check(this.form.list)">//这个form不是form名字