Html Button clicking help

Okay well I have been trying to make a visual basics program that buys a product when it is available. So the program inserts the text box product number into the form and then clicks check availability, without reloading the page, a second button appears if the product on the website is available. And then the second button is then clicked. If the second button doesn't exist yet the program loops and starts over again until the second button is available. This code is currently what I have. The program begins to loop and then freezes. Any help would be appreciated.

What I have so far

Code:

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  WebBrowser2.Document.GetElementById("product").SetAttribute("value", TextBox3.Text)
  Do Until WebBrowser2.DocumentText.Contains("button id=""BuyIt""")
    WebBrowser2.Document.GetElementById("checkAvailability").InvokeMember("click")
  Loop

  WebBrowser2.Document.GetElementById("BuyIt").InvokeMember("click")

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These are the buttons

Code:

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<button id="checkproduct" type="submit" style="display: inline"> Check Availability of Product </button>
<button id="buyIt" type="submit" style="display: none"> Buy it </button>

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seems like it will click something until it appears, cant you put something along these lines

Code:

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do until browser.readystate = 4 'or "complete"
loop

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browser is what you have called it (WebBrowser2)