function IsNumeric(strString)
   //  check for valid numeric strings	
   {
   var strValidChars = "0123456789.-";
   var strChar;
   var blnResult = true;

   if (strString.length == 0) return false;

   //  test strString consists of valid characters listed above
   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         {
         blnResult = false;
         }
      }
   return blnResult;
   }
   
   
   
   function calculate()
{

// if  (document.calcform.course[0].selected) {
// document.calcform.courseprice.value = 123;
// }
// 
// if  (document.calcform.course[1].selected) {
// document.calcform.courseprice.value = 222;
// }
var minweeks = 1; //default
var maxweeks = 48; //default

var enrolfee= 100; //from db

//get accomm price
var my_price=document.calcform.accomm.options[document.calcform.accomm.selectedIndex].value;
var my_price_array=my_price.split("_");
document.calcform.accommprice.value = my_price_array[1];
document.calcform.accommtype.value = my_price_array[0];



//get course details
var course_details=document.calcform.course.options[document.calcform.course.selectedIndex].value;
var course_details_array= course_details.split("_");
document.calcform.coursename.value = course_details_array[0]; 
document.calcform.courseprice.value = course_details_array[1];


if (course_details_array[2] !=""){
var minweeks = course_details_array[2];
}

if (course_details_array[3] !=""){
var maxweeks = course_details_array[3];
}


//var maxweeks = course_details_array[3];



//max courseweeks 
   if (document.calcform.courseweeks.value > maxweeks*1){
document.calcform.courseweeks.value = maxweeks;
}

//min courseweeks from db
   if (document.calcform.courseweeks.value < minweeks*1){
document.calcform.courseweeks.value = minweeks;
}


//check for numeric input

if (IsNumeric(document.calcform.courseweeks.value) == false) 
      {
document.calcform.courseweeks.value = '';
      }
      
      
//enrolment fee
if (document.calcform.courseweeks.value > 0 )
{document.calcform.efee.value = enrolfee}
else
{document.calcform.efee.value = 0}


// deposit depends on no of weeks
if (document.calcform.courseweeks.value > 25 )
{document.calcform.deposit.value = 500}
else
{document.calcform.deposit.value = 100}



//accomweeks same as courseweeks
document.calcform.accommweeks.value  = document.calcform.courseweeks.value 



// calc total
document.calcform.coursetotal.value = (document.calcform.courseprice.value)*(document.calcform.courseweeks.value)


document.calcform.accommtotal.value = (document.calcform.accommprice.value)*(document.calcform.accommweeks.value)


//document.calcform.accommtotal.value = (document.calcform.accommprice.value)*(document.calcform. courseweeks.value)


document.calcform.total.value = eval(document.calcform.coursetotal.value) + eval(document.calcform.efee.value)+ eval(document.calcform.accommtotal.value)

}