function subst() { var vars = {}; var query_strings_from_url = document.location.search.substring(1).split('&'); for (var query_string in query_strings_from_url) { if (query_strings_from_url.hasOwnProperty(query_string)) { var temp_var = query_strings_from_url[query_string].split('=', 2); vars[temp_var[0]] = decodeURI(temp_var[1]); } } var css_selector_classes = Object.keys(vars); for (var css_class in css_selector_classes) { if (css_selector_classes.hasOwnProperty(css_class)) { var element = document.getElementsByClassName(css_selector_classes[css_class]); for (var j = 0; j < element.length; ++j) { element[j].textContent = vars[css_selector_classes[css_class]]; } } } }