console
function checkboxed(objName){
var objNameList=document.getElementsByName(objName);
if(null !=objNameList){
alert("全选操作");
for(var i=0;i<objNameList.length;i++){
objNameList[i].checked="checked";
}
}
}
function uncheckboxed(objName){
var objNameList=document.getElementsByName(objName);
if(null!=objNameList){
alert("取消反选操作");
for(var i=0;i<objNameList.length;i++){
objNameList[i].checked="";
}
}
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=, initial-scale=">
<meta http-equiv="X-UA-Compatible" content="">
<title></title>
</head>
<body>
看书: <input type="checkbox" name="checkbox" value="1"><br>
写字： <input type="checkbox" name="checkbox" value="2"><br>
打飞机: <input type="checkbox" name="checkbox" value="3"><br>
玩游戏: <input type="checkbox" name="checkbox" value="4"><br>
<button onclick="checkboxed('checkbox')">全选</button>
<button onclick="uncheckboxed('checkbox')">取消全选</button>
</body>
</html>