Getting URL Parameters

gistfile1.js

function campaignParams() {
            var campaign_keywords = 'utm_source utm_medium utm_campaign utm_content utm_term'.split(' ')
                , kw = ''
                , params = {}
                , first_params = {} ;

			var index;
			for (index = 0; index < campaign_keywords.length; ++index) {
                kw = getQueryParam(document.URL, campaign_keywords[index]);
                if (kw.length) {
                    params[campaign_keywords[index] + ' [last touch]'] = kw;
                }
			}
			for (index = 0; index < campaign_keywords.length; ++index) {
                kw = getQueryParam(document.URL, campaign_keywords[index]);
                if (kw.length) {
                    first_params[campaign_keywords[index] + ' [first touch]'] = kw;
                }
			}
		
            mixpanel.register(params);
		    mixpanel.people.set(params);
            mixpanel.register_once(first_params);
            mixpanel.people.set_once(first_params);
            
        }