9、class获取、添加删除状态切换 - HTML5&CSS3.0基础部分-xyphfwindow.var oBtn =

1、class——获取样式名or长度

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
<script>
window.onload = function(){
    var oBtn = document.getElementById('btn1');

    oBtn.onclick = function(){
        //alert(this.className);
        //alert(this.classList.length);
        //alert(this.tagName);
        //alert(this.classList[1]);
    };
};
</script>
</head>
<body>
    <input id="btn1" class="add active box" type="button" value="按钮" />
</body>
</html>

2、class——添加删除

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
<script>
window.onload = function(){
    var oBtn = document.getElementById('btn1');

    oBtn.onclick = function(){
        //this.classList.add("active");//添加一个样式
        //this.classList.remove("active");//删除一个样式

        //alert(this.classList.contains("add1"));//判断是否包含一个样式

        this.classList.toggle("active");//添加删除一个样式状态切换
    };
};
</script>
</head>
<body>
<input id="btn1" class="add active box active active active" type="button" value="按钮" />
</body>
</html>