If checkbox is checked, change a value.

[Barney Clausen]

Hi. I'm having this minor, but probably simple problem. I'm making a form that's calculating some numbers, the result depends on which checkboxes (box3 & box4) the user chooses and values the user puts in. However I can't get Javascript and my checkboxes to work together. When a user checks a checkbox, it's supposed
to change a value in the calculation, however all it outputs is "0on". box1 & box2 Works perfectly (They're both text-boxes).

 function runTotal(myForm) 
   {
 
    var form_field1=Number(myForm.box1.value);
    var form_field2=Number(myForm.box2.value * 1.005);
    var form_field3=(myForm.box3.value);
    var form_field4=(myForm.box4.value);
 
    // Nu kommer post-numre priserne ind i systemet.
 
    if (form_field1 == "7800")
    {
        var form_field1=200
    }
 
    if (form_field1 == "7100") 
    {
        var form_field1=300
    }
 
 
   myForm.total.value = form_field1 + Math. ceil(form_field2) + form_field3 + form_field4;
 
   }
   function checkIt(f){
    if(f.box3.checked)
    {
    var form_field3=560
    }
    else
    {
    var form_field3=0

[Shenno]

CheckBoxobject.checked will return current boolean current state..

u can use it to make anything..