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Change of code in browser

I'm using a drop down list for selecting customer, from that i need to remove the setTimeout which i shown in the image, i don't know from where to remove it..can any one suggest me from where it loads..my browser alone show the <select .. >, i need to know from where it loads..
<td><asp:DropDownList Width="180px" CssClass="select_quo_one" ID="ReceiverDropDown"
runat="server" AutoPostBack="true"
OnSelectedIndexChanged="ReceiverDropDown_SelectedIndexChanged">
</asp:DropDownList>
</td>
My Browser Code:

Seems to me you have a few choices -
1) Remove the AutoPostBack - this will stop the SelectedIndexChanged event firing but as you only seem to be popping up an alert you could probably recreate this client side.
2) Put the DropDownList in an UpdatePanel as explained to you in your other question, you may need to do a bit of debugging to get this working but should do what you want.
3) Accept the page reload - accept this is the trade-off when using Web Forms and leave as is.
4) Move to something like MVC which does not have the Postback model.
Sounds like you probably need to do some reading into Web Forms and look at the Pros and Cons and make an informed decision as at the moment you are trying to fight the framework rather than work with it.

The setTimeout is automatically generated by the DropDownList control because AutoPostBack is set to true.
From http://msdn.microsoft.com/en-us/library/system.web.ui.postbackoptions.autopostback(v=vs.110).aspx
The JavaScript setTimeout method is used with the _doPostBack method to ensure that the user action completes before the postback occurs.
Edit:
"flickering occurs in my page so i have to remove the setTimeout value.. – user3595072 17 mins ago"
The setTimeout itself is not (directly) causing the page flickering. The flickering is because the DropDownList is doing a postback every time it is changed bc AutoPostBack is set to true and this causes the page to refresh. If you are not doing anything server side immediately after a customer is selected (like loading other customer info on the page), then you can just set AutoPostBack to false. Otherwise you can look into using an UpdatePanel on your page, or use something like AJAX calls to do your processing without a full postback.
Edit 2:
Since you are only adding javascript within your AutoPostBack event, you can add a jQuery reference (if you do not have one already) by adding the following to your ASPX page:
<script src="//code.jquery.com/jquery-1.11.0.min.js" type="text/javascript"></script>
Then set AutoPostBack="false" on your DropDownList and add this javascript to accomplish the same thing that your AutoPostBack was doing:
<script type="text/javascript">
$(function () {
$('#<%=ReceiverDropDown.ClientID %>').on('change', function (e) {
var benId = $(this).val();
if (benId != '' && benId != '0') {
AddDetails(benId);
}
});
});
</script>

OnSelectedIndexChange not firing even with autopostback=true

Ok I'm a little stumped here. I have an asp:Dropdownlist on the page. It gets populated via a web service call like this:
Ajax.GetSubDevelopments(developmentId, function (results) {
var subDevelopments = $j("#<%=ddlMinorAssociation.ClientID %>");
subDevelopments.empty();
$j('<option />', { value: "-1", text: "Select a sub association" }).appendTo(subDevelopments);
$j.each(results, function (index, value) {
$j('<option />', { value: value.SubDevelopmentID, text: value.Name }).appendTo(subDevelopments);
});
subDevelopments.show();
});
The actual control itself looks like this:
<asp:DropDownList ID="ddlMinorAssociation"
OnSelectedIndexChanged="ddlMinorAssociation_SelectedIndexChanged"
AutoPostBack="true" runat="server" CssClass="hidden">
</asp:DropDownList>
The intent is that when the user selects a subdevelopment, it will postback and then bind a datalist of results. Now the page is posting back, Page.Request.Params.Get("__EVENTTARGET") even says that it was posting back due to the drop down list. However, none of the code in my ddlMinorAssociation_SelectedIndexChanged function is being run. Here is that code:
protected void ddlMinorAssociation_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write("hi");
}
Can anyone offer some insight as to what is going on???

I believe the issue is related to the fact that when the page loaded, there were no elements in the dropdown list and ViewState didn't have any information of selected items; therefore, when it posts back, it determines that there hasn't been any IndexChanged event to fire.
The fact that it posts back is just because the Autoposback property is set to true which basically fires a normal form submit.
If you want this to work, change the AutoPostback property to false and hook code to the onchange event instead, then fire another Ajax request to whatever method you need to execute on the server side and bind the data on the client side.

Server-side, you dropdown list does not have any items. It cannot fire OnSelectedIndexChanged event because its index has not changed - it has no items to give it a meaningful current index value.

How do you call OnPageIndexChanging from Javascript?

I have code that when a user wants to page through a GridView, it asks them (using a JavaScript confirm) if they want to save the data from the grid.
So, I'm able to get the confirm to work (with the code-behind saving function), but I'm noticing that it's not firing the OnPageIndexChanging method - which basically defeats the purpose here.
So, to summarize, can JavaScript access the OnPageIndexChanging method?
Thanks a lot

The OnPageIndexChanging event is a server-side event, so it's not surprising that your Javascript handler isn't getting triggered.
I'm not sure if ASP.Net has a "built in" way to do this; but you can do it by attaching your own Javascript listeners. Here is the general approach (I'm using JQuery to make it easier):
Write a JQuery selector that gets all the paging links that you want to confirm.
Add a click listener for each of those links
Make the confirm function the handler for those listeners
So, the code would look something like this:
$("#grid a").each(function () {
$(this).click(function () {
return confirm("really?");
});
});
Notes
Here grid is the ID of the GridView control, so #grid a selects every a tag within my grid.
Using return confirm() returns false if the user does not confirm, which effectively cancels the click event.

How to submit a form without postback in asp.net?

I have a form in asp.net webpage which contains 2 drop down lists and a hyperlink + a button.
I want that if user changes an option is dropdowns to change navigate url.
I have done like so:
<asp:DropDownList ID="ddlPackages" AutoPostBack ="true" runat="server"
onselectedindexchanged="ddlPackages_SelectedIndexChanged"></asp:DropDownList>
and then I have the method defined.
The point is that I don't want to make a submit when I change the drop down. Can I do it using only aspx or I have to use javascript?

If I understand you correctly you want to change the href of the hyperlink based on the selected value of the dropdown. You can do this with javascript. Make sure you have AutoPostBack="false" and remove the OnSelectedIndexChanged attribute as well.
To do it using jQuery, use something like this:
<script type="text/javascript>
$(function(){
var $dropdown = $('#<%= ddlPackages.ClientId %>');
$dropdown.change(function(){
//Put logic to decide the link here based on the select value
var newPage = 'page' + $dropdown.val() + '.aspx';
$('#linkId').attr('href', newPage);
});
});
</script>
Edit:
In case you absolutely must have the logic for getting the new url based on the drop down value on the server side, you can turn the method into a Page Method and call it using ajax from the jQuery script above. But you can probably get away with creating the javascript dynamically in the aspx page instead.

I see two options:
1) Wrap the controls in an Update Panel (.NET 3+). Put AutoPostBack=true on the dropdownlist, and define a SelectedIndexChange event for it that changes the hyperlink control's Navigate URL property. When the user changes the dropdown, you're method will fire without the APPEARANCE of a form submission. Downside: there's a slight delay between the dropdown changing and the link changing. If your server is really, really slow, this delay could potentially cause problems (but this is probably unlikely).
2) Use custom JavaScript and do away with your .NET controls completely. This is what I would probably do, assuming you don't need to do anything else with these controls programatically. Your JavaScript function would monitor the dropdown for a SelectedINdexChange and adjust the href attribute of the anchor tag accordingly. Look into jQuery to speed up development if you aren't too familiar with plain JavaScript.

If the control is an ASP:DropDownList, you can use the AutoPostBack="True|False" property to prevent a postback

If you don't want to use the AutoPostBack you have to post the form using jQuery or Javascript
You can add an event on your drop down list onchange and add the code you need to post the form usin jQuery:
$('#formId').submit();
http://api.jquery.com/submit/
If you to want navigate to another Url add the below code at your DropDownList control (make sure AutoPostBack=false)
onchange="window.location.href='yourUrl'"
it would be better put that Javascript on a separate file anyway

During PostBack JavaScript losing its functionality

I have one GridView which has one CheckBox and three TextBoxes in its template column.
The logic is, when I check the CheckBox, the corresponding TextBoxes should get enabled. If I uncheck the CheckBox, then the corresponding TextBoxes should get disabled. I have written JavaScript for this functionality.
Everything is working fine, but in that page I have one DropDownList too. When I change the DropDownList value, the page gets PostBack and at that time I lost the JavaScript functionality, i.e. the enabled TextBoxes in the GridView gets disabled. How to solve this problem?

After every post back in the update panel you need to reinitialize your javascript, because as you understand the struct of the html has change and javascript runs on the previous one that not exist after the update panel updates. Microsoft gives a functionality to do that as follow.
This is javascript lines.
<script type="text/javascript">
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(InitializeRequest);
prm.add_endRequest(EndRequest);
function InitializeRequest(sender, args) {
}
function EndRequest(sender, args) {
// here initialize again your javascript
}
</script>

Use the RowCreated event for the ASP Grid to add the client function on the check box, this way the client function will stay on each postback

You must register your javascript at each postback for it to run, by using the ScriptManager.RegisterStartupScript method: here's an example (edited for article in english, sorry :p).

Use auto post back with check box to enable disable text box from server side code. This will update the view state and so it will be maintained on select change. Use these inside UpdatePanel for ajax. Alternatively, you can add drop down into updatepanel as well, so that select change does not affect other page elements.

JavaScript is working on DOM. When page gets PostBack values from ViewState are written to DOM and overwrites your JavaScript changes. You should store state of checkboxes in persistent way ie. jQuery data() or hiddenfield and after PostBack write changes back to DOM.