jquery - Copy to clipboard multiple items -

i doing copy clipboard picking first id. understand because can't have multiple id's when change code document.getelementsbyclassname doesn't work?

following code

 function copytoclipboard() {         var input = document.getelementbyid("toclipboard");         var texttoclipboard = input.value;          var success = true;         if (window.clipboarddata) { // internet explorer             window.clipboarddata.setdata("text", texttoclipboard);         }         else {             // create temporary element execcommand method             var forexecelement = createelementforexeccommand(texttoclipboard);              /* select contents of element                 (the execcommand 'copy' method works on selection) */             selectcontent(forexecelement);              var supported = true;              // universalxpconnect privilege required clipboard access in firefox             try {                 if (window.netscape && netscape.security) {                     netscape.security.privilegemanager.enableprivilege("universalxpconnect");                 }                  // copy selected content clipboard                 // works in firefox , in safari before version 5                 success = document.execcommand("copy", false, null);             }             catch (e) {                 success = false;             }              // remove temporary element             document.body.removechild(forexecelement);         }          if (success) {             alert("the text on clipboard");         }         else {             alert("your browser doesn't allow clipboard access!");         }     }      function createelementforexeccommand(texttoclipboard) {         var forexecelement = document.createelement("div");         // place outside visible area         forexecelement.style.position = "absolute";         forexecelement.style.left = "-10000px";         forexecelement.style.top = "-10000px";         // write necessary text element , append document         forexecelement.textcontent = texttoclipboard;         document.body.appendchild(forexecelement);         // contenteditable mode necessary  execcommand method in firefox         forexecelement.contenteditable = true;          return forexecelement;     }      function selectcontent(element) {         // first create range         var rangetoselect = document.createrange();         rangetoselect.selectnodecontents(element);          // select contents         var selection = window.getselection();         selection.removeallranges();         selection.addrange(rangetoselect);     } 

and here html;

<div id="app-details"><span>activation guid</span><br /><br /> <input id="toclipboard" value="@appdetails.activationguid"> <button onclick='copytoclipboard ()'>copy guid</button></div> 

thanks.