Traversal and branch judgment of JS (case on June 24, 2022)

/*
    Time ：2022 year 6 month 24 Japan
    author ：FairyKunKun
 */
var gridData = s_detail1Obj.getData ();
var sum3 = 0;//sum3 It is used to record that the document number starts with 3 The total number of the order No
var sum4 = 0;//sum4 It is used to record that the document number starts with 4 The total number of the order No
if ( gridData.length > 0 ) { // Traverse all data and count all forms 3、4 Total at the beginning
   for ( i = 0 ; i < gridData.length ; i ++ ) {
      if ( gridData[ i ].inbb001.substr ( 0 , 1 ) == "3" ) {
         //alert(gridData[i].inbb001.substr(0,1));
         sum3 ++;
      } else {
         //alert(gridData[i].inbb001.substr(0,1));
         sum4 ++;
      }
   }
}
if ( sum3 > 0 && sum4 === 0 ) { // If only the form starts with 3 Of
   document.getElementById ( "sptj001" ).value = "3";
   // Assign a value to the target table box “3”
} else if ( sum4 > 0 && sum3 === 0 ) { // If only the form starts with 4 Of
   document.getElementById ( "sptj001" ).value = "4";
   // Assign a value to the target table box “4”
} else {
   document.getElementById ( "sptj001" ).value = "5";
   // In other cases “5”
}