function saveRecord(scriptContext) {
 var rec = scriptContext.currentRecord;
 var itemLineCount = rec.getLineCount({
  sublistId: "item"
 });

 if (itemLineCount > 0) {
  for (var lineNum = 0; lineNum < itemLineCount; lineNum++) {
   //selecting lines in the Item Receipt
   rec.selectLine({
    sublistId: "item",
    line: lineNum
   });
   //check if line has subrecord
   if (!rec.hasCurrentSublistSubrecord({
     sublistId: "item",
     fieldId: "inventorydetail"
    })) {
    continue;
   }
   //get Inventory Detail form with target value (Bin)
   var invDetDyn = rec.getCurrentSublistSubrecord({
    sublistId: "item",
    fieldId: "inventorydetail"
   });
   //iterating through lines in Inventory detail
   var lineInInvDet = 0;
   while (true) {
    /* Impossible to get number of lines on the subrecord. Possible reason is that the currentRecord is in the dynamic mode
     * try...catch used for catching cases, when we considered every line. Non existing line throws an error.
     */
    try {
     invDetDyn.selectLine({
      sublistId: "inventoryassignment",
      line: lineInInvDet
     });
    } catch (error) {
     //no more lines in the Inventory Detail form
     break;
    }
    // getting bin value with no problems
    var binValue = invDetDyn.getCurrentSublistValue({
     sublistId: "inventoryassignment",
     fieldId: "binnumber"
    });

    var binField = invDetDyn.getSublistField({
     sublistId: "inventoryassignment",
     fieldId: "binnumber",
     line: lineInInvDet
    });
    // inside the console log I can see the field, but most
    // of it's values are undefined.
    //the most interesting for me is the getSelectOptions,
    // which should allow me to get all options
    console.log(binField);
    lineInInvDet++;
   }
  }
 }
 return true;
}