int getStringStartIndex(string $string1, string $string2)

•Searches for $string2 in $string1 and returns the index into $string1 where $string2 starts.

•The index is 0 based. For example, if $string2 is contained in the very beginning of $string1, then the function returns 0.

•If $string2 is not in $string1, then the function returns -1.

•Performs a case-insensitive search.