Dynamic CRM 365 Editable grid get and set selected row column value

When you bind the javascript on field change event check the context from UI and define the javascript function name like this:

 var year;  
 var weekNumber;  
 var selectedRow = null;  
 var attributeColl = null;  
 function dateChange(eContext) {  
   debugger;  
   var nameAttr = eContext.getEventSource();  
   var attrParent = nameAttr.getParent();  
   var startDateField = attrParent.attributes.get("new_startdate");  
   var date = startDateField.getValue();  
   //Get week number  
   var currentWeekNumber = parseFloat(date.getWeek());  
   //Get full year  
   const dt = new Date(date);  
   var currentyear = parseFloat(dt.getFullYear());  
   //set week value  
   var new_weeknumbercstField = attrParent.attributes.get("new_weeknumbercst");  
   new_weeknumbercstField.setValue(currentWeekNumber);  
   // Set year value  
   var new_yearcstField = attrParent.attributes.get("new_yearcst");  
   new_yearcstField.setValue(currentyear);  
 }  
 Date.prototype.getWeek = function() {  
   var onejan = new Date(this.getFullYear(), 0, 1);  
   return Math.ceil((((this - onejan) / 86400000) + onejan.getDay() + 1) / 7);  
 }