How js controls css

Methods for js to control css: 1. Change the style through the style attribute or "setAttribute()"; 2. Change the "content" content of the pseudo class "(after, before)"; 3. By changing the class name to change the style, etc.

The operating environment of this article: windows7 system, javascript1.8.5&&CSS3 version, DELL G3 computer

How does js control css?

Several ways for JS to control css styles

In our work and study of js, we always encounter some situations where it is not easy to dynamically load css styles through the style attribute. situation (eg: pseudo-class style control, animation style control), here is a summary of several ways to change the style in js:

1, change the style through the style attribute or setAttribute()

ele.style.width='50px';//最常用
ele.style.cssText='width:50px';//并不会覆盖原先所有css
ele.style.setProperty("width", "50px", "important");//可以传第三个参数
ele.setAttribute("style", "width: 50px")//也不会覆盖原先所有css放心用

ele.style.width='50px';//最常用
ele.style.cssText='width:50px';//并不会覆盖原先所有css
ele.style.setProperty("width", "50px", "important");//可以传第三个参数
ele.setAttribute("style", "width: 50px")//也不会覆盖原先所有css放心用

2, if you just change the content of the pseudo class (after, before), you can also do this

//css代码
div::after{
    content:attr(data-myadd);
    width:10px;
}
//js代码
div.setAttribute('data-myadd',需要动态加载的内容)

//css代码
div::after{
    content:attr(data-myadd);
    width:10px;
}
//js代码
div.setAttribute('data-myadd',需要动态加载的内容)

3, change the style by changing the class name

ele.className='';
ele.classList.add();//emmmm没什么好说的

ele.className='';
ele.classList.add();//emmmm没什么好说的

4, then the key point is Now: Using document.styleSheets we get all the style sheets, and then select a style sheet to add styles through insertRule; you can also create new cssRules and add styles through addRule()

document.styleSheets：获取到的是所有样式列表的集合
href：通过link标签引入的样式表，则是样式表的URL，否则为null
media：当前样式表支持的所有媒体类型集合
type：样式表类型的字符串
disabled： 通过disabled来屏蔽掉该样式表，可以用来切换样式表 ； document.styleSheets[i].disabled = true
cssRules：是当前样式列表的所有样式集合；document.styleSheets[i].cssRules
cssText：当前样式表的某一个样式的样式document.styleSheets[i].cssRules[i].cssText
selectorText：当前样式的选择符
parentStyleSheet：当前规则所属样式表；IE不支持
insertRule(rule,index)：在index前插入一条rule新规则； document.styleSheets[0].insertRule('* {background:blue;color:#000}',0)不支持IE；document.styleSheets[0].addRule('*',' {background:blue;color:#000}',0)支持IE；
deleteRule(index)：删除某个央视列表的第index个样式；IE用removeRule(index)
//使用document.styleSheets获取样式表的时候最好获取最后一个，在最后一个样式表上添加样式
var sheets=document.styleSheets;
var lastSheet=sheets[sheets.length-1];
lastSheet.insertRule('#div{width:10px}',index)//将#div样式直接添加到cssRules中;index是添加到第几条;现代浏览器
lastSheet.addRule('div','width:10px;',0)//IE浏览器

//使用document.styleSheets获取样式表的时候最好获取最后一个，在最后一个样式表上添加样式
var sheets=document.styleSheets;
var lastSheet=sheets[sheets.length-1];
lastSheet.insertRule('#div{width:10px}',index)//将#div样式直接添加到cssRules中;index是添加到第几条;现代浏览器
lastSheet.addRule('div','width:10px;',0)//IE浏览器

5, dynamically load styles Table

If there are many styles that need to be changed, it is recommended to change the page style by dynamically loading styles

//改变样式文件的引用
function loadStyle(url){
　　var link = document.createElement('link');
    link.type = 'text/css';
    link.rel = 'stylesheet';
    link.href = url;
    var head = document.getElementsByTagName('head')[0];
    head.appendChild(link);
}
loadStyle('test.css');
//动态加载css代码片段
var style = document.createElement('style');
    style.type = 'text/css';
    style.rel = 'stylesheet';
    try{ //Chrome Firefox Opera Safari
        style .appendChild(document.createTextNode(code));
    }catch(ex){//IE
        style.styleSheet.cssText = code;
    }
    var head = document.getElementsByTagName('head')[0];
    head.appendChild(style);
}
loadCssCode('body{background-color:#f00}');

//改变样式文件的引用
function loadStyle(url){
　　var link = document.createElement('link');
    link.type = 'text/css';
    link.rel = 'stylesheet';
    link.href = url;
    var head = document.getElementsByTagName('head')[0];
    head.appendChild(link);
}
loadStyle('test.css');
 
//动态加载css代码片段
var style = document.createElement('style');
    style.type = 'text/css';
    style.rel = 'stylesheet';
    try{ //Chrome Firefox Opera Safari
        style .appendChild(document.createTextNode(code));
    }catch(ex){//IE
        style.styleSheet.cssText = code;
    }
    var head = document.getElementsByTagName('head')[0];
    head.appendChild(style);
}
loadCssCode('body{background-color:#f00}');

Recommended study: "javascript Advanced Tutorial"

The above is the detailed content of How js controls css. For more information, please follow other related articles on the PHP Chinese website!