Searches an element using the given selector, it's type and an optional
elemId to start the search from and tells whether it exists on page. See description at check element exists.
elementExists(using, by) # Or elementExists(elemId, using, by)
elemId: Element that must be the parent of the desired element. Search for the element starts from here.
stringselector used to search element. See details of using.
byconstant. The type of selector. See details of by.
booleanindicating the result