Alternatives to using delays when automatically testing an AJAX web UI

public void MinAndMaxPriceRestoredWhenOpenedAfterUsingBackButton(){
  OpenBrowserTo("welcome/index.rails");
  bot.Click("priceDT");
  WaitForText("Price Range");
  WaitForText("515 N. County Road");
  bot.Select("MaxDropDownList", "$5,000,000");
  WaitForText("Prewar 8 Off Fifth Avenue");
  bot.Select("MinDropDownList", "$2,000,000");
  WaitForText("of 86");
  bot.Click("link=Prewar 8 Off Fifth Avenue");
  WaitForText("Rarely available triple mint restoration");
  bot.GoBack();
  Thread.Sleep(20000);
  bot.Click("priceDT");
  WaitForText("Price Range");
  Assert.AreEqual("$5,000,000", bot.GetSelectedLabel("MaxDropDownList"));
  Assert.AreEqual("$2,000,000", bot.GetSelectedLabel("MinDropDownList"));}

public void MinAndMaxPriceRestoredWhenOpenAfterUsingBackButton(){
  OpenBrowserTo("welcome/index.rails");
  ClickLink("Price");
  SelectMaxPrice("$5,000,000");
  SelectMinPrice("$2,000,000");
  ClickLink("Prewar 8 Off Fifth Avenue");
  GoBack();
  ClickLink("Price");
  Assert.AreEqual("$5,000,000", SelectedMaxPrice());
  Assert.AreEqual("$2,000,000", SelectedMinPrice());}

// Wait until the value of the watintoken attribute is changed
ie.SelectList("countries").WaitUntil(!Find.By("watintoken",watintoken));

public void MinAndMaxPriceRestoredWhenOpenAfterUsingBackButton(){
  ActiveBrowser.NavigateTo("welcome/index.rails");
  Find.ByContent<HtmlAnchor>("Price").Click();
  HtmlSelect maxPrice = Find.ById<HtmlSelect>("MaxDropDownList");
  HtmlSelect minPrice = Find.ById<HtmlSelect>("MinDropDownList");
  maxPrice.SelectByText("$5,000,000");
  minPrice.SelectByText("$2,000,000");
  Find.ByContent<HtmlAnchor>("Prewar 8 Off Fifth Avenue").Click();
  ActiveBrowser.GoBack();
  Find.ByContent<HtmlAnchor>("Price").Click();
  maxPrice.AssertSelect().SelectedText("$5,000,000");
  minPrice.AssertSelect().SelectedText("$2,000,000");}