lovecoding
/
VIP32


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <ul id="list">
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
    </ul>
    <div id="btn">添加</div>
    <!-- 事件委托: 减少内存消耗 避免多次循环 -->
    <script>
        var list = document.querySelectorAll("#list li")
        var lis = document.getElementById("list");
        var btn = document.getElementById("btn")
        // console.log(list)
        // for(var i=0;i<list.length;i++) {
        //     console.log(list[i]);
        //     list[i].onclick = function() {
        //     }
        // }
        lis.onclick = function(event) {
            // console.log(event);
            if(event.target.nodeName == 'LI') {
                console.log(event.target.innerHTML);
            }
        }
        btn.onclick = function() {
            var li1 = document.createElement("li");
            li1.innerHTML = Math.round(Math.random() * 9 + 1);
            lis.appendChild(li1);
        }
    </script>
</body>
</html>