FiloSottile

import HTMLParser

class IDParser(HTMLParser.HTMLParser):
    """Modified HTMLParser that isolates a tag with the specified id"""
    def __init__(self, id):
        self.id = id
        self.result = None
        self.started = False
        self.depth = {}
        self.html = None

FiloSottile

page.clipRect = page.evaluate(function() {
    return document.getElementById(ELEMENT_ID).getBoundingClientRect(); 
});