CODEWITHSUNDEEP
javascriptasp.net
user1134487
user1134487

Reputation:

Problems accessing ASP.NET Controls from JavaScript

Sorry for the basic silly question. But I really dont have any idea on how to solve this. I have ASP controls (One TextBox and One DropDownList). Now I need to access value property of TextBox as well as SelectedIndex property of DropDownList. This should be as simple as:

For TextBox:

document.getElementById("<%= myControl.ClientID >").value

For DropDownList:

document.getElementById("<%= myControl.ClientID %>").selectedindex

But in Visual Studio 2008, while I am writing these codes, it does not work. I can not find any value or selectedindex attribute for the respective control. I am not getting this, because in most forums and tutorials, they suggested in a simple way I mentioned.

HTML Code:

<div> <asp:TextBox ID="myText" runat="server" /> <asp:DropDownList ID="myList" runat="server" /> </div>

Is there any other way or I am just missing something here?

Upvotes: 0

Views: 5543

Answers (3)

balexandre
balexandre

Reputation: 75073

first of all, jQuery helps you a lot writting javascript, you shoudl use this path.

To answer your question, you need to use MyControlId.ClientID and not only MyControlId

for example:

var t = document.getElementById('<%= myTextBoxID.ClientID %>').value;
alert(t);  // textbox value

var d = document.getElementById('<%= myDropDownID.ClientID %>'),
    dSelected = d.options[d.selectedIndex].value;
alert(dSelected); // dropdown value

with jQuery this would simply be:

var t = $('#<%= myTextBoxID.ClientID %>').val(),   // for your textbox
    d = $('#<%= myDropDownID.ClientID %>').val();  // for your selectbox 
alert(t ' --> ' + d);

Seams, from the comments that you still have no luck, then the problem must be in the control or the name itself, try this to debug the problem:

let's imagine that you have:

<asp:TextBox runat="server" id="MyTextBox" Text="Hello" />

write right below that line this:

<h2><%= MyTextBox.ClientID %></h2>

and open the inspector of your browser (Firebug or IE Dev tools) and run the javascript to see if you get the Hello string, like this:

Note: I used MyTextBox, please change it to the name that you got inside that <h2> tag

enter image description here

Upvotes: 1

keyboardP
keyboardP

Reputation: 69372

Try using a single punctuation mark.

document.getElementById('<%= myTextBox.ClientID %>').value

A couple of answers recommend jQuery but I think you should only use it if you need it. If you're only getting values from elements, then there shouldn't be a need to introduce a new library to your website. If you plan to use quite a bit of Javascript, animations, etc.. then jQuery would make sense.

Upvotes: 0

akiller
akiller

Reputation: 2472

Personally I'd use jQuery instead of standard JavaScript and then have a look at this question for how to find your element with it.

edit: if you haven't used jQuery before then make sure you wrap your code in its ready block otherwise it might not find your element:

$(document).ready(function() {
  // work with your element ID here
});

Upvotes: 0

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