Problém s onChange funkcí

<SCRIPT TYPE="text/javascript">
<!-- 
function orderTotal(oform)
{
// set references to fields
var start_price = oform["start_price"];
var stHold = oform["stHold"];

var stVis = oform["stVis"];

// only bother if the field has contents
if (start_price == "")return;

// if the with is not a number (NaN)
// or is zero or less
// everything goes blank
if(isNaN(start_price.value) || (start_price.value <= 0))
   {
   start_price.value = "";
   stHold.value = "";
   }
   
// else the field is a valid number, so calculate the 
// total order cost and put that value in the 
// hidden subtotal field
else
   stHold.value = (Math.round(start_price.value * 1 * 100))/100;

// call the routine which checks if the 
// visible subtotal is correct
visTotal(oform);
}

// checks if the visible subtotal is correct
// ie, if it equals the hidden subtotal field
function visTotal(oform)
{
var stHold = oform["stHold"];
var stVis = oform["stVis"];

if (stVis.value != stHold.value)
   stVis.value = stHold.value;
}
// -->
</SCRIPT>

<TABLE BORDER CELLPADDING=3>
<!-- table titles -->


<!-- v-neck sweater -->
<TR BGCOLOR="#FFFFCC">
   
   <TD><INPUT TYPE=TEXT NAME="start_price" SIZE=3 
         onChange="orderTotal(this.form, 'start')" 
         ></TD>
   
   <TD ALIGN=RIGHT>
      <INPUT TYPE=HIDDEN NAME="stHold">
      <INPUT TYPE=TEXT NAME="stVis" SIZE=10 
         onChange="visTotal(this.form)" 
         ></TD>
   </TR>


</TABLE>