:()()1-6:()(value){
hobby = .()hobby2 = .()
(i hobby&&hobby2){
i.= value}
}
(){
()}
(){
()}
(){
()j=.().hobby2 = .(+ j ).(hobby2)( !hobby2){
()}
hobby2.= }<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<body>
<form>
请选择你爱好:<br>
<input type="checkbox" name="hobby" id="hobby1"> 音乐
<input type="checkbox" name="hobby" id="hobby2"> 登山
<input type="checkbox" name="hobby" id="hobby3"> 游泳
<input type="checkbox" name="hobby" id="hobby4"> 阅读
<input type="checkbox" name="hobby" id="hobby5"> 打球
<input type="checkbox" name="hobby" id="hobby6"> 跑步 <br>
<input type="button" value="全选" onclick="checkall();">
<input type="button" value="全不选" onclick="clearall();">
<p>请输入您要选择爱好的序号，序号为1-6:</p>
<input id="wb" name="wb" type="text">
<input name="ok" type="button" value="确定" onclick="checkone();">
</form>
<script type="text/javascript">
function checkall() {
var hobby = document.getElementsByTagName("input");
// 任务1
for (var i = 0; i < hobby.length; i++) {
if (hobby[i].type == 'checkbox') {
hobby[i].checked = true
}
}
}
function clearall() {
var hobby = document.getElementsByName("hobby");
// 任务2
for (var i = 0; i < hobby.length; i++) {
if (hobby[i].type == 'checkbox') {
hobby[i].checked = false
}
}
}
function checkone() {
var j = document.getElementById("wb").value;
// 任务3
if(j>=1 && j <=6){
var hobby = document.getElementsByTagName("input");
hobby[j - 1].checked = true
}
}
</script>
</body>
</html>