SetAttribute (Value) To A TextBox In A WebPage Document In VB?

how to SetAttribute (a Value) for a textbox in a webpage document that don't have an ID .I already knows that to SetAttribute to a textbox you just need the ID of the element.

I.E : WebBrowser1.document.GetElementByID(THE ELEMENT ID).SetAttribute("Value",TextBox1.text)

So as you see in the example, to set attribute to an Element I need an ID and in my case I don't know what is the ID of the Specific Element.

This is the ViewSource of the Textbox :

<input name="ctl00$ContentPlaceHolder$ccEnterCode" type="text" size="5" maxlength="5" value="">

I don't see where's the ID !