Fix to output checked checkboxes properly as concatenated string (dwyl#89)

* Fix to output checkbox groups properly as concatenated string

* Add comments to JS

Author: martynhoyer

form-submission-handler.js

@@ -19,13 +19,21 @@ function getFormData() {
   var data = {};
   fields.forEach(function(k){
     data[k] = elements[k].value;
-    if(elements[k].type === "checkbox"){
-      data[k] = elements[k].checked;
-    // special case for Edge's html collection
+    var str = ""; // declare empty string outside of loop to allow
+                  // it to be appended to for each item in the loop
+    if(elements[k].type === "checkbox"){ // special case for Edge's html collection
+      str = str + elements[k].checked + ", "; // take the string and append 
+                                              // the current checked value to 
+                                              // the end of it, along with 
+                                              // a comma and a space
+      data[k] = str.slice(0, -2); // remove the last comma and space 
+                                  // from the  string to make the output 
+                                  // prettier in the spreadsheet
     }else if(elements[k].length){
       for(var i = 0; i < elements[k].length; i++){
         if(elements[k].item(i).checked){
-          data[k] = elements[k].item(i).value;
+          str = str + elements[k].item(i).value + ", "; // same as above
+          data[k] = str.slice(0, -2);
         }
       }
     }