Question

I am trying to change the value on a hidden field in a WebBrowser control.

I can inject Javascript that displays an alert box. I can make the alert box show the current value of the hidden field. However, I cannot get the value of the hidden field to change.

I have tried changing the value by doing this (tb is the WebBrowser control):

HtmlElement head = tb.Document.GetElementsByTagName("head")[0];
HtmlElement scriptEl = tb.Document.CreateElement("script");
IHTMLScriptElement element = (IHTMLScriptElement)scriptEl.DomElement;
element.text = "function DoIt() { document.getElementById('TestHiddenField').value='Hello World'; alert('Updated'); }";
head.AppendChild(scriptEl);
tb.Document.InvokeScript("DoIt");

In the above the alert does pop up.

And I have tried this:

tb.Document.Body.InnerHtml = tb.Document.Body.InnerHtml.Replace("MyValue", "YourValue");

In the above I see that the InnerHtml does change when debugging.

However, when the page is done loading and I view source the value is never changed.

Also, Even though I can inject javascript to and it pops up the alert, I am never able to find the javascript int the code.

What’s going on? What am I doing wrong?

Thanks!

UPDATES:

• I’m doing this in the DocumentCompleted event.

• I’m not using ViewState

ANOTHER UPDATE:

I added another field. This time a non-hidden text field.

<input type="hidden" id="TestHiddenField" value="MyValue" name="TestHiddenField" />
<input type="text" id="TestField" value="MyValue" name="TestField" />

Here is what happens when I do this:

tb.Document.Body.InnerHtml = tb.Document.Body.InnerHtml.Replace("MyValue", "YourValue");

When the page renders in the WebBrowser Control the text box displays the text “YourValue” but when I View Source the value still equals “MyValue”.

What’s up with that? I need for it to equal “YourValue”.

Any ideas?

Thanks again!

Answer 1

However, when the page is done loading and I view source the value is never changed.

Do not alter the DOM until after the page is done loading. You have to wait for the DocumentCompleted event to fire.