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How jquery determines if a checkbox is selected

Source: Internet
Author: User
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All know in HTML If a check box is selected is Checked= "checked".

But if we use jquery alert ($ ("#id"), attr ("checked") will prompt you to be true instead of checked

So many friends judge if ($ ("#id"). attr ("checked") = = "true") this is wrong and should actually be if ($ ("#id"). attr ("checked") ==true)

Examples include a few features.

<input type= "button" id= "BTN1" value= "Select All" >
<input type= "button" id= "Btn2" value= "deselect All" >
<input type= "button" id= "Btn3" value= "Check all odd" >
<input type= "button" id= "Btn4" value= "Reverse Selection" >
<input type= "button" id= "Btn5" value= "Get All selected Values" >

Code

<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 transitional//en" >
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<meta http-equiv= "Content-type" content= "text/html; Charset=utf-8 "/>
<script language= "JavaScript" src= "Http://www.cnjquery.com/demo/jquery.js" ></script>
<script language= "JavaScript" >
<!--
$ ("document"). Ready (function () {

$ ("#btn1"). Click (function () {

$ ("[name= ' checkbox ']"). attr ("Checked", ' true ');//Select All

})
$ ("#btn2"). Click (function () {

$ ("[name= ' checkbox ']"). Removeattr ("checked");//Cancel Select all

})
$ ("#btn3"). Click (function () {

$ ("[name= ' checkbox ']:even"). attr ("Checked", ' true ');//Select All odd

})
$ ("#btn4"). Click (function () {

$ ("[name= ' checkbox ']"). each (function () {


if ($ (this). attr ("checked"))
{
$ (this). Removeattr ("checked");

}
Else
{
$ (this). attr ("Checked", ' true ');

}

})

})
$ ("#btn5"). Click (function () {
var str= "";
$ ("[name= ' checkbox '][checked]"). each (function () {
str+=$ (This). Val () + "" R "N";
Alert (This). Val ());
})
alert (str);
})
})
-
</SCRIPT>

</HEAD>

<BODY>
<form name= "Form1" method= "Post" action= "" >
<input type= "button" id= "BTN1" value= "Select All" >
<input type= "button" id= "Btn2" value= "deselect All" >
<input type= "button" id= "Btn3" value= "Check all odd" >
<input type= "button" id= "Btn4" value= "Reverse Selection" >
<input type= "button" id= "Btn5" value= "Get All selected Values" >
<br>
<input type= "checkbox" name= "checkbox" value= "CheckBox1" >
CheckBox1
<input type= "checkbox" name= "checkbox" value= "CheckBox2" >
CheckBox2
<input type= "checkbox" name= "checkbox" value= "Checkbox3" >
Checkbox3
<input type= "checkbox" name= "checkbox" value= "Checkbox4" >
Checkbox4
<input type= "checkbox" name= "checkbox" value= "CHECKBOX5" >
Checkbox5
<input type= "checkbox" name= "checkbox" value= "checkbox6" >
Checkbox6
<input type= "checkbox" name= "checkbox" value= "CHECKBOX7" >
checkbox7
<input type= "checkbox" name= "checkbox" value= "Checkbox8" >
Checkbox8
</form>


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Related Keywords:
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