getMax.js

/**
 * Find the maximum value of an element in a subform
 * @param  {array} myArray       Subform
 * @param  {string} column       Data column name to aggregate
 * @return {int|boolean}         The maximum value found, or false if array is undefined or data column name is not found
 */
function getMax(myArray, column) {
   if (typeof myArray == "undefined" || myArray == null || Array.isArray(myArray) === false) return false;

   var max_value = false;
   for (var i = 0; i < myArray.length; i++) {
      if (typeof myArray[i][column] !== "undefined") {
         if (max_value === false) {
            max_value = myArray[i][column];
         } else {
            if (Number(max_value) < Number(myArray[i][column])) {
               max_value = myArray[i][column];
            }
         }
      }
   }

   return max_value;
}