This Function allows it to highlight assigned Parts (needle) of a string (hystack) with pre defined HTML-Tags by only once call of function. Surely, in PHP4 it would be much
easier to realise such a function - but this function works in PHP3, too. To define the tags that highlight the needle in the hystack-string use an array consisting of two
values [0] (for opening the tag(s)) and [1] (for closing the tag(s)). The function doesn't do any echo's, it only returns the value, so you have to call it in order with echo to
write what it returns.