JavaScript获取、修改CSS样式合辑

时间：2023-03-09 01:13:07
JavaScript获取、修改CSS样式合辑 
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    <meta http-equiv="X-UA-Compatible" content="ie=edge">

    <title>Document</title>

    <style>

        #box{

            height: 200px;

            width: 200px;

            color: white;

            background-color: orange;

        }

    </style>

</head>

<body>

    <div style="text-align:center;" id="box">

        <span style="font-size:20px;" id="txt">测试样例哈</span>

    </div>

    <script>

        var box = document.getElementById("box");

        var txt = document.getElementById("txt");

        //1 .style.property 仅能获取内联样式 但可以修改样式

        console.log(box.style.textAlign);//center

        console.log(box.style.color);//空白

        // box.style.color = "black";//√

        //不可加！important

        //2 .style.cssText

        console.log(box.style.cssText);//text-align:center, 返回

        // txt.style.cssText = "color:red;";//注意，会覆盖之前的样式，包括在这里没有写到的，相当于清除了原本元素的样式

        //但是继承而来的样式不会被清除,如这里继承自box的居中对齐

        //可加！important，如用来覆盖继承的属性

        //3 .style.setProperty

        txt.style.setProperty("font-size","30px");//√

        //仅可用于部分常用属性

        //4 document.defaultView(window).getComputedStyle

        //IE则是currentStyle[attr]

        var declaration =  document.defaultView.getComputedStyle(box,null);

        var detailStyle =  document.defaultView.getComputedStyle(box,null).height;

        // var declaration =  document.defaultView.getComputedStyle(box,null)[height];//同理

        var windowDeclaration = window.getComputedStyle(box,null);

        console.log(declaration,windowDeclaration,detailStyle);

        //4.sp 封装一个具有兼容性的属性查阅函数

        function styleCheck (element,prop,state){

            if(document.defaultView.getComputedStyle(element,state)){

                result = document.defaultView.getComputedStyle(element,state)[prop];//不能.prop哈，记得

            }else{

                result = element.currentStyle.prop;

            }

            console.log("The value of property"+ prop + " is" + " " + result + ".");

            return result;

        }

        styleCheck(box,"height");

        //5. 对样式表下手 insertRule 与 addRule

        // var changedStyleSheet = document.styleSheet[0].insertRule("#box","height","400px"); 插入新规则

    </script>

</body>

</html>

相关文章