链接
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
</head>
<style>
ul {
list-style: none;
}
</style>
<body>
<ul>
<li>全选<input type='checkbox' id='all'></li>
<li>Java<input type='checkbox' class='item'></li>
<li>javaScript<input type='checkbox' class='item'></li>
<li>C++<input type='checkbox' class='item'></li>
<li>python<input type='checkbox' class='item'></li>
<li>.net<input type='checkbox' class='item'></li>
</ul>
<script>
// 补全代码
var all = document.querySelector("#all");
var options = Array.from(document.querySelectorAll(".item"));
all.onchange = function() {
for(let i of options) {
i.checked = all.checked;
}
}
function updateAllbtn() {
let r = true;
for(let i of options) {
r = r&&i.checked;
}
if(r) {
all.checked = true;
} else {
all.checked = false;
}
}
options.forEach(i => {
i.onchange = function() {
updateAllbtn();
}
})
</script>
</body>
</html>
