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Copy codeThe Code is as follows:
$ ("Select"). change (function (){
Var n = $ (this). children (). length;
Var obj;
Var I = 1;
$ (This). children (). each (function (){
If (I = n)
{
Alert ($ (this). text ());
}
I ++;
});
});
Based on the above two methods, I can easily achieve what I want:
Copy codeThe Code is as follows:
Function selectall ()
{
$ ("Select"). children (). each (function () {$ (this). attr ("selected", "selected ")})
}
Children () and $ (this). attr ("selected", "selected ")
One js usage
Copy codeThe Code is as follows:
<! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<Html xmlns = "http://www.w3.org/1999/xhtml">
<Head>
<Meta http-equiv = "Content-Type" content = "text/html; charset = gb2312"/>
<Script type = "text/javascript">
<! --
Function selectAll ()
{
Var opts = document. getElementById ("CourseList ");
For (var I = 0; I <opts. length; I ++)
{
Opts [I]. selected = true;
}
}
// -->
</Script>
</Head>
<Body>
<Select id = "CourseList" name = "CourseList" multiple = "multiple" size = "20" style = "width: 230px;">
<Option value = "003"> (003) Consumer Behavior and sales psychology </option>
<Option value = "004"> (004) Product Planning and marketing </option>
<Option value = "005"> (005) brand positioning and advertising principles </option>
</Select>
<Input type = "button" onclick = "selectAll ()" value = "select all">
</Form>
</Body>
</Html>
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