console 命令行工具 X clear

console

var checkAll=false;
function allcheck(){
    checkAll = !checkAll;
    let inputs=document.getElementsByName('checkbox');
    for(var i=0;i<inputs.length;i++){
        inputs[i].checked=checkAll;
    }
}

<!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="allcheck()">全选/取消</button>
</body>
</html>