How to get the link URL parameters in the address bar

1  // first value band link for 
2   function the getQueryString (name) {
 . 3      var REG = new new the RegExp ( "(^ | &)" + name + "= ([^ &] *) (& | $) "," I " );
 . 4      var R & lt window.location.search.substr = (. 1 ) .match (REG);
 . 5      IF ! (R & lt = null ) return unescape (R & lt [2]); return  null ;
 . 6  }
 . 7   var Promotion the getQueryString = ( 'P' );
 . 8  
. 9  // second parent page acquired by value 
10   function urlParams (paramName) {
 . 11      var reg = new RegExp("[\?&]" + paramName + "=([^&]*)[&]?", "i");
12     var paramVal = window.location.search.match(reg);
13     return paramVal == null ? "" : decodeURIComponent(paramVal[1]);
14     }
15 //取相关的值
16 var openId = urlParams('openId');
17 var lessonId = urlParams('lessonId');