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Hidden value is always null

Posted on 2013-11-13
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Last Modified: 2013-11-14
Hi Expert,

I created a HiddenField control:
 <asp:HiddenField runat="server" ID="hiddenisCheckedout" />


And I set value to the hidden field from code behind:

if (isCheckedout())
{
     hiddenisCheckedout.Value = "true";
}
else
{
     hiddenisCheckedout.Value = "false";
}


And then I retrieve the value in Javascript:
        var isChked = document.getElementById('hiddenisCheckedout');
        alert(isChked);

But isChked is always null. It shoud be the value I setup from code behind. Please help.

Appreciated!!
0
Comment
Question by:jssong2000
  • 4
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10 Comments
 
LVL 23

Expert Comment

by:Rajkumar Gs
ID: 39645503
Hi
Try adding  .value
document.getElementById('hiddenisCheckedout').value;
       
Raj
From Mobile
0
 
LVL 23

Expert Comment

by:Rajkumar Gs
ID: 39645516
If not works try

document.getElementById('<%= hiddenisCheckedout.ClientID %>'').value;
0
 

Author Comment

by:jssong2000
ID: 39645518
It does not allow me to do this. Only valueof available on the list when I type "." Thanks!
0
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LVL 83

Expert Comment

by:leakim971
ID: 39645526
try this :
var isChked = document.getElementById('<%= hiddenisCheckedout.ClientID %>');
alert( isChked ? isChked.value : "field not found" );

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0
 

Author Comment

by:jssong2000
ID: 39645599
field not found

so the hidden field has problem.
0
 
LVL 83

Expert Comment

by:leakim971
ID: 39645601
do a right click on the page in your web browser, choose view source and post it here
0
 

Author Comment

by:jssong2000
ID: 39645784
<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>

</title></head>
<body>
    <form method="post" action="Default.aspx" id="form1">
<div class="aspNetHidden">
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="izwqc5WQZyDCR+BuJMRPJMse5OYwgnLKs8wVFArRTZAwVacizcc/aBGavK5C7Qa7GU74j1XrkyiwlC8OWUN2/iWUAZ4AlUY4IC1lqDL4Ykw=" />
</div>

<div class="aspNetHidden">

	<input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="Ol14+jgIk+FbIeTSdI5ltslouQ0rO/ZO3WcKopuYsoxYGB+63ej8hyE7uMYBFO6Dirz+VvnpC+wvSgAbgZVSKVEsGJ+TMsdV+pSp41hK2GWbH9cIhnmvNmQTQTIUNnhmSZOTKD1bP8jRIiLUvjMaAA==" />
</div>
               <script type="text/javascript">
                   var isChked = document.getElementById('hiddenisCheckedout');
                   alert(isChked ? isChked.value : "field not found");



                   function getCookie(c_name) {
                       var c_value = document.cookie;
                       var c_start = c_value.indexOf(" " + c_name + "=");
                       if (c_start == -1) {
                           c_start = c_value.indexOf(c_name + "=");
                       }
                       if (c_start == -1) {
                           c_value = null;
                       }
                       else {
                           c_start = c_value.indexOf("=", c_start) + 1;
                           var c_end = c_value.indexOf(";", c_start);
                           if (c_end == -1) {
                               c_end = c_value.length;
                           }
                           c_value = unescape(c_value.substring(c_start, c_end));
                       }
                       return c_value;
                   }
                   function setCookie(c_name, value, exdays) {
                       var exdate = new Date();
                       exdate.setDate(exdate.getDate() + exdays);
                       var c_value = escape(value) + ((exdays == null) ? "" : "; expires=" + exdate.toUTCString());
                       document.cookie = c_name + "=" + c_value;
                   }

                   //alert('test1 = ' + getCookie('test1'));
                   //setCookie('test1', null, 1);
                   //alert('test1 again ==' + getCookie('test1'));


               </script>
    <div>
    
    </div>
        <p>
            Hello</p>
        <p>
            &nbsp;</p>
        <input type="submit" name="Button1" value="Button" id="Button1" />
         <input type="hidden" name="hiddenisCheckedout" id="hiddenisCheckedout" value="false" />
    </form>
</body>
</html>

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0
 
LVL 83

Expert Comment

by:leakim971
ID: 39645812
replace :
      var isChked = document.getElementById('hiddenisCheckedout');
                   alert(isChked ? isChked.value : "field not found");
by :
window.onload = function() {
      var isChked = document.getElementById('hiddenisCheckedout');
                   alert(isChked ? isChked.value : "field not found");
}

or put your script at the end of the page
else you can't get a reference of a field not already present in the page, the html of field is loaded after the script and it's execution

using window.onload wait the complete loading of the page
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LVL 83

Accepted Solution

by:
leakim971 earned 2000 total points
ID: 39645818
0
 

Author Closing Comment

by:jssong2000
ID: 39648565
Great job. Appreciated!!
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