//--------------------------------------------------
    function WB_Plot(weight, moment)
    {
      // Left-margin on the graph is 114 pixels...
      var x = Math.round(114 + ((moment - 45000) / 10000) * 69) - 15;
      var y = 259 - Math.round(((weight - 1500) / 100) * 27.3) - 15;

	  with (document.images.crossHairImage.style)
	  {
	    left = x + 'px';
	    top  = y + 'px';
	   	visibility = "visible";
	  }
    }

    //--------------------------------------------------
    function WB_Calculate()
    {
      with (document.WBCalc)
      {

	if (!WB_ValidateInput()) return;
           
	fuelWeight.value = fuelQuant.value * 6; //calculate fuel weight

        totalWeight.value = 
          (Number(emptyWeight.value) +
           Number(frontWeight.value) +
           Number(rearWeight.value)  +
           Number(fuelWeight.value)  +
           Number(baggageWeight.value)).toString();

        emptyMoment.value =
          (Math.round(Number(emptyWeight.value)   * Number(emptyLever.value))).toString();
        frontMoment.value =
          (Math.round(Number(frontWeight.value)   * Number(frontLever.value))).toString();
        rearMoment.value =
          (Math.round(Number(rearWeight.value)    * Number(rearLever.value))).toString();
        fuelMoment.value =
          (Math.round(Number(fuelWeight.value)    * Number(fuelLever.value))).toString();
        baggageMoment.value =
          (Math.round(Number(baggageWeight.value) * Number(baggageLever.value))).toString();

        totalMoment.value =
          (Number(emptyMoment.value) +
           Number(frontMoment.value) +
           Number(rearMoment.value)  +
           Number(fuelMoment.value)  +
           Number(baggageMoment.value)).toString();

        // Show the crosshair on the graph...
        WB_Plot(Number(totalWeight.value), Number(totalMoment.value));
      }
    }

    function WB_Reset()
    {
      with (document.WBCalc)
      {
        // Set the fields to their default values...
        emptyWeight.value   = "1456.80";
        frontWeight.value   = "";
        rearWeight.value    = "";
        fuelQuant.value     = "37";  // Full fuel by default
        baggageWeight.value = "";

        emptyLever.value    = "37.63";
        frontLever.value    = "35.90";
        rearLever.value     = "70.00";
        fuelLever.value     = "47.75";
        baggageLever.value  = "95.80";

	// N1383U book values:

        emptyWeight.value   = "1456.80";
        emptyLever.value    = "39.02";
        frontLever.value    = "37.00";
        rearLever.value     = "73.00";
        fuelLever.value     = "47.80";
        baggageLever.value  = "95.00";

        fuelQuant.value     = "48";  // Full fuel by default

      }

      // Hide the crosshair on the graph...
      document.images.crossHairImage.style.visibility = "hidden";

      // Calculate based on empty values...
      WB_Calculate();
    }