Below is just the code without chrome debug for better view:
saveChanges : function(){
var oView = this.getView();
var oController = oView.getController();
alert("Value entered " +oController.getuserval());
},
getuserval: function(oVal){
var oCore = sap.ui.getCore();
oVal = oCore.byId("QI");//You will get id here.
return oVal;
},