<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<script type="text/javascript">
window.onload=function(){
var allCheck=document.getElementById("FirstCheck")
var fruitElts=document.getElementsByName("fruit")
allCheck.onclick=function(){
if(allCheck.checked){
for(var i=0;i<fruitElts.length;i++){
fruitElts[i].checked=true
}
}else{
for(var i=0;i<fruitElts.length;i++){
fruitElts[i].checked=false
}
}
}
var all=fruitElts.length//获取选项框总数
for(var i=0;i<fruitElts.length;i++){
fruitElts[i].onclick()=function(){
var checkedCount=0//计数器归零
for(var j=0;j<fruitElts.length;j++){
if(fruitElts[j].checked){
checkedCount++
}//判断选项框状态,如果被勾选则计数器加一
}
allCheck.checked=(all==checkedCount)//判断计数器总数和选项框总数是否相等,若相等则勾选全选框
}
}
}
</script>
<input type="checkbox" id="FirstCheck" />全选<br />
<input type="checkbox" name="fruit" />苹果<br />
<input type="checkbox" name="fruit" />香蕉<br />
<input type="checkbox" name="fruit" />桃子
</body>
</html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<script type="text/javascript">
window.onload=function(){
var allCheck=document.getElementById("FirstCheck")
var fruitElts=document.getElementsByName("fruit")
allCheck.onclick=function(){
if(allCheck.checked){
for(var i=0;i<fruitElts.length;i++){
fruitElts[i].checked=true
}
}else{
for(var i=0;i<fruitElts.length;i++){
fruitElts[i].checked=false
}
}
}
var all=fruitElts.length//获取选项框总数
for(var i=0;i<fruitElts.length;i++){
fruitElts[i].onclick()=function(){
var checkedCount=0//计数器归零
for(var j=0;j<fruitElts.length;j++){
if(fruitElts[j].checked){
checkedCount++
}//判断选项框状态,如果被勾选则计数器加一
}
allCheck.checked=(all==checkedCount)//判断计数器总数和选项框总数是否相等,若相等则勾选全选框
}
}
}
</script>
<input type="checkbox" id="FirstCheck" />全选<br />
<input type="checkbox" name="fruit" />苹果<br />
<input type="checkbox" name="fruit" />香蕉<br />
<input type="checkbox" name="fruit" />桃子
</body>
</html>
fruitElts[i].onclick()=function(){
改成
fruitElts[i].onclick=function(){