lovecoding
/
web0715


			
				
					
						
						
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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>
    <div class="container">
        <div class="list-item">
            <span>div1</span>
            <button class="up-btn">向上按钮</button>
            <button class="down-btn">向下按钮</button>
        </div>
        <div class="list-item">
            <span>div2</span>
            <button class="up-btn">向上按钮</button>
            <button class="down-btn">向下按钮</button>
        </div>
        <div class="list-item">
            <span>div3</span>
            <button class="up-btn">向上按钮</button>
            <button class="down-btn">向下按钮</button>
        </div>
    </div>
    <script>
        var upBtn = document.getElementsByClassName("up-btn");
        var downBtn = document.getElementsByClassName("down-btn");

        var oContainer = document.getElementsByClassName("container")[0];
        for(var i=0;i<upBtn.length;i++){
            downBtn[i].onclick = function(){
                var oParent = this.parentElement;
                var nextParent = oParent.nextElementSibling;
                // console.log(nextParent);
                if(nextParent){
                    oContainer.insertBefore(nextParent,oParent)
                }else{
                    console.log("到底了")
                }
                // js中除了 undefind null ""(空字符) 0 false  其他全为真;
            }
            upBtn[i].onclick = function(){
                var oParent = this.parentElement;
                var preParent = oParent.previousElementSibling;
                if(preParent){
                    oContainer.insertBefore(oParent,preParent);
                }else{
                    console.log("到顶了")
                }
            }
        }
    </script>
</body>
</html>