VB righting Text to Webpage

Hey Guys

I am trying to write some code that will write text into a textarea of a webpage.
I can't seem to get it to work. I'm new to coding and the what I am trying to get done I thought was simple enough. But my ignorance to coding has hit a road block.

My coding looks like this (VB 2013)

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
WebBrowser1.Navigate("https:xxxxxxxxxx")
WaitForPageLoad()

Dim textArea As HTMLTextAreaElement

textArea = WebBrowser1.Document.GetElementById("addbulk").DomElement
textArea.value = TextBox1.Text

End Sub


The textarea I want to add to on the webpage


<form name="bulkadd" method="post" action="?view=bulkadd">

<p>Bulk add field:<br></p>

<input name="view" value="bulkadd" type="hidden">

<textarea name="bulkadd" cols="100" rows="10" onfocus="this.value = ( this.value == this.defaultValue ) ? '' : this.value;return true;">Enter CSV in the following format:

Please enter text here
</textarea>
<br>

<a href="?view=bulkadd" class="navbutton" onclick="document.submit();return false;">Submit</a>

<a href="#" class="navbutton" onclick="document.bulkadd.reset();return false;">Clear Bulk Form</a>

</form>

I would like if it added the text as text box1 is filled with information. But at this stage I would be happy to just get it to populate the webpage textarea with the text that the user will put into textbox1.

I have searched the web. But have yet to find the answer.
Thanks in advance for any help.