def click_at(self,locator,coordString):
self.do_command("<STR_LIT>", [locator,coordString,])<EOL>
Clicks on a link, button, checkbox or radio button. If the click action
causes a new page to load (like a link usually does), call
waitForPageToLoad.

'locator' is an element locator
'coordString' is specifies the x,y position (i.e. - 10,20) of the mouse      event relative to the element returned by the locator.