JS modifies the class attribute in HTML __c language

Using JS to modify the HTML class attribute value, summed up under:

First, get the class attribute value

var value = $ ("div"). attr ("class")//Here Gets the class attribute value
var array=val.split ("");//separate the class value by a space, and get each value through the array

var value = document.getElementById ("div"). ClassName;

Change the value of class attribute

document.getElementById ("tr"). ClassName = "Styleclass";//styleclass for the new property value
document.getElementById ("tr"). SetAttribute ("Class", "Styleclass");

Third, add a class attribute (on the original basis)

var obj = document.getElementById (' A1 ');
Obj.classname + = ' styleclass '; Note that the preceding space prevents two properties from being combined

Four, remove a class attribute

$ ("tr"). Removeclass ("Styleclass");

Other:

1. Determine if there are attributes in the class attribute:

if (Value.indexof ("Styleclass") >= 0) {}

2. Change the border of select through CSS

<span style= "border:1px solid #7FFF00; Position:absolute; Overflow:hidden ">
<select style=" margin:-1px "> 
    <option>aaa</option> 
    <option >bbb</option> 
</select> 
</span>