It is great class you made that Simple Page Crawler does.
I have two idea you may add to the class:
1. Option to grab page using curl which is supported in most modern php hosting (sometimes they disable php get url function default)
2. I don't know if this has been addresed, but how if I want to get the text within a js script which produced html code or even xml code? Facebook uses a js script which produce xml code containing text/html code with css tags. Does it all stripped too when we use the class function which stipped SCRIPT tags? I will interested to get those text inside a js containing html/xml/css tags.