How to wait for an alert in Selenium webdriver ? [duplicate]

No default method for waiting for alert.

but, you can write your own method something like this.

waitForAlert(WebDriver driver)
{
   int i=0;
   while(i++<5)
   {
        try
        {
            Alert alert = driver.switchTo().alert();
            break;
        }
        catch(NoAlertPresentException e)
        {
          Thread.sleep(1000);
          continue;
        }
   }
}