How to get elementbyid in javascript?

Question

I have a masterpage in which i defined a function for getElementById .

function Clear() {
    document.getElementById('<%= NameTextBox.ClientID  %>').value = "";
    document.getElementById('<%= LastNameTextBox.ClientID  %>').value = "";
}

when i use this function in other page it is clearing the element value.

but when i use this code in masterpage, i get error :

The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).

[HttpException (0x80004005): The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).]
 System.Web.UI.ControlCollection.Add(Control child) +9601391
AjaxControlToolkit.ScriptObjectBuilder.RegisterCssReferences(Control control) +691
AjaxControlToolkit.ScriptControlBase.OnLoad(EventArgs e) +44
System.Web.UI.Control.LoadRecursive() +54
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Control.LoadRecursive() +145
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +772

if i change my code to :

document.getElementById('<%# NameTextBox.ClientID  %>').value = "";

i don't get error. but don't clear myelement.

take page source in browser and check the server side code rendered as you expected. or you can check in firebug console for any js error. — Mithun Satheesh, Dec 26 '12 at 06:50
try `document.getElementById('ctl00_NameTextBox').value = "";` — Satinder singh, Dec 26 '12 at 06:59
http://stackoverflow.com/questions/778952/the-controls-collection-cannot-be-modified-because-the-control-contains-code-bl — Manish Mishra, Dec 26 '12 at 07:07

score 0 · Accepted Answer · answered Dec 26 '12 at 06:56

0

Looks like you have added mentioned js function in <Head> tag of master page. Instead try adding your js function in <form> tag in master page at end.

answered Dec 26 '12 at 06:56

Amit Thakkar

356
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How to get elementbyid in javascript?

1 Answers1