var url = location.href;
//Get keyword Parameter value
var es=/keyword=/;
es.exec(url);
var result=RegExp.rightContext;
For example:
var url = location.href;
//Get the pid Parameter value
var es=/pid=/;
es.exec(url);
var pid=RegExp.rightContext;
var aurl = "&pid=" pid;
alert(pid);//result :&pid=37