I'm using the javascript below to read the value of an asp.net control in the client-side. However, it always returns the null value. I'm using similar code at other pages in my website, but now i can't read this specific control. Please suggest anyways I can fix this problem.
<asp:Label ID="srch_data" runat="server" ClientIDMode="Static" ></asp:Label>
var srch_data = document.getElementById("<%= srch_data.ClientID %>");
alert(srch_data);
Try using single quotes:
var srch_data = document.getElementById('<%= srch_data.ClientID %>').value;
Try this
var srch_data =document.getElementById('srch_data').innerHTML;
ASP.Net Label becomes span after rendering so instead of finding a label which can not be recognized by JS better find
Add the defer attribute to your script element. I tested and it worked.
Try something like below -
<%--defer indicates the script to be run after the document is completely parsed.--%>
<script type="text/javascript" language="javascript" defer="true">
var label = document.getElementById("<%= srch_data.ClientID %>");
alert("label : " + label);
</script>
<asp:Label ID="srch_data" runat="server" ClientIDMode="Static"></asp:Label>
This should fix your issue.
Related
I did try searching and I tried all the solution provided and I still cannot get this to work, the javascript is returning null for while trying to get the element ID of the grid view. How can I get the client ID of the gridview, from the web browser it is showing as --> id="ctl00_ContentPlaceHolder1_GridView5"
function Validate() {
var GridID = document.getElementById('<%= GridView5.ClientID %>');
alert(GridID);
}
<asp:GridView ID="GridView5" runat="server" OnRowDataBound="GridView5_RowDataBound" AutoGenerateColumns = "False" HorizontalAlign="Center">
What am I doing that's wrong?
Please try this,
var grid = $("[id*=GridView5]")
or use
var grid = $("#<%=GridView5%>")
write this line in current page script
As the Javascript code is in the external file, you cannot use <%= GridView5.ClientID %> expression.
I would suggest you to set the GridView.ClientIDMode="Static" and use the below code to acces gridview in external javascript file.
if this is your gridview
<asp:GridView ID="GridView5" runat="server" OnRowDataBound="GridView5_RowDataBound" AutoGenerateColumns = "False" HorizontalAlign="Center" ClientIDMode="Static">
then use theblow code
var grid = $("#GridView5");
thank you for the suggestion. This worked for me as my java scripts are in a separate file.
var tbl = document.getElementById("GridView5");
I work on ASP.NET c#. I have a DropDownList. (runat="server")
On $(document).ready, I updated its value:
$(document).ready(function () {
document.getElementById("ddl").value = "abc";
…
When I get back to the Server (c#), there is no value in the ddl:
ddl.SelectedValue == ""
What could be the problem?
Thanks,
YYY
as far your dropdown runat="server" it has generated ClientID, "ddl" it's serverside id, on client you need to call like shown below
document.getElementById("<%= ddl.ClientID %>").value = "abc";
Welcome to the wonderful world of WebForms: in the list of things this framework screws up is ID's of your runat="server" elements
When the engine processes your server markup it generates own id's based on the place where you declared that particular element. Check it in your browser devtools.
Luckily since ASP.NET 4 you can specify special attribute ClientIDMode and now you can do it like
<asp:TextBox ID="txt" runat="server" ClientIDMode="Static" />
which will render like
<input id="txt" name="ctl00$MasterPageBody$ctl00$txt" />
If you cannot use for some reason ASP.NET 4, you can stick to old solution as #Dan proposed:
document.getElementById("<%= ddl.ClientID %>")
But this is not the recommended way.
EDIT
Probably you should do ddl.SelectedItem.Value instead.
I want to set the value of a asp.net textbox using javascript
My JS Code is:
document.getElementById('<%=txtFlag.ClientID %>').value = "Track";
My textbox is:
<asp:TextBox ID="txtFlag" runat="server" Visible="False"></asp:TextBox>
But it gives me an error document.getElementById(...)' is null or not an object
I dont understand what is wrong.
Please help.
<asp:TextBox ID="txtFlag" runat="server" Visible="False"></asp:TextBox>
Setting visible=false will cause this textbox to not appear in the rendered page. Remove this, and add display:none;
<asp:TextBox ID="txtFlag" runat="server" style="display:none;"></asp:TextBox>
Try including the ClientIDMode property in your textbox
<asp:TextBox ID="txtFlag" runat="server" Visible="False"
ClientIDMode="Static"></asp:TextBox>
You are calling javascript before complete document load. Please write your javascript code on document.ready function like this
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script type="text/javascript">
$(document).ready(function() {
document.getElementById('<%=txtFlag.ClientID %>').value = "Track";
});
</script>
And second thing is that use display none in place of visible false or use hidden field control
<asp:TextBox ID="txtFlag" runat="server" style="display:none;"></asp:TextBox>
Solution 1:
Make that textbox as visible=true and try,
When you make a control as visible false, that control will not be loaded in client side and as you knew javascript will be executed on client side itself.
Solution 2:
Add this javascript at the end of the page.
document.getElementById('txtFlag').value='Track'
try this
I am simply trying to store a label in a variable in javascript but for some reason this isn't working with document.getElementById('control');. I know my javascript is linking to my html file fine because everything else works.
Here is my javascript code:
function performEvapCooledCircuit(txt)
{
var error = document.getElementById('lblError');
if (txt.value == null || isNaN(txt.value))
{
error.style.visibility = "visible";
}
}
Here is the html code for my label:
<asp:Label ID="lblError" class="NormLabel" runat="server"
style="color:red; visibility:hidden;" Text="Invalid Input."></asp:Label>
I am getting an error that says object expected??
The ID that ASP.NET will generate will not be "lblError" so you'll need to reference it by its ClientID
document.getElementById('<%=lblError.ClientID %>');
If your javascript file is external I've usually had to write a type of "Init" javascript method to make sure my ID's were set up property
On your ASPX page:
<script type="text/javascript">
var lblError = null;
function InitializeVariables()
{
if (lblError == null) // make sure you only do this once
{
lblError = document.getElementById("<%=lblError.ClientID %>");
}
}
</script>
<asp:Label
ID="lblError"
class="NormLabel"
runat="server"
style="color:red; visibility:hidden;"
Text="Invalid Input."></asp:Label>
Then in your javascript file you'll have to call InitializeVariables() to make sure you've got the variables pointing to the proper asp.net controls
function performEvapCooledCircuit(txt)
{
InitializeVariables();
if (txt.value == null || isNaN(txt.value))
{
lblError.style.visibility = "visible";
}
}
"hunter" gives a pretty solid way of doing things, however a, in my opinion far better method is to use the "CliendIDMode" property on the control and set that property to "Static". This will make the client and server IDs the same. Like this:
<asp:TextBox ID="ServerAndClientId" runat="server" ClientIDMode="Static" />
The ID of the label is not "lblError". The ASP.net engine changed the ID. Check the HTML source code in the browser to find out the real ID.
That's not HTML for the label, that is an ASP.NET Control which will be rendered into HTML before it is sent in the response. ASP.NET WebForms controls sometimes change the id for the HTML they create.
View the source of the webpage to see what the id for the HTML element is on the rendered page.
You can use this:
document.getElementById('<%= lblError.ClientID %>').click()
Starting from ASP.NET 4.0 you can use ClientIDMode property for you element. And if you set it into Static then the ClientID value will be set to the value of the ID property:
<asp:Label ID="lblError" runat="server" ClientIDMode="Static" />
will be rendered as something like this:
<span id="lblError" name="ctl00$MasterPageBody$ctl00$Label1" />
What I'm trying to do is get an asp:button to click. The only problem is that it is within a few tags.
Example:
<loginview>
<asp:login1>
<logintemplate>
//asp:textbox and asp:button are located here.
</loginview>
</asp:login>
</logintemplate>
So how would I get javascript to point to that location so that I can manipulate it. For example, get the button to click.
First, you need to figure out which template is being used, since you can only access the active one. (Anonymous or LoggedIn). Once you do that, use the FindControl method on the LoginView to find the ClientID of the element you need to reference.
For example:
<form runat="server">
<asp:LoginView runat="server" ID="LoginView">
<AnonymousTemplate>
<asp:Button ID="ASPButton" Text="Button" runat="server" />
</AnonymousTemplate>
</asp:LoginView>
</form>
<script type="text/javascript">
var el = document.getElementById('<%= LoginView.FindControl("ASPButton").ClientID %>');
</script>
Check out the jQuery framework: you can find controls by ID, and then call methods/properties on those controls.
http://jquery.com/