Onchange select

[adamjblakey]

Hi,

I have 2 lists in a form one for a type of property and the other for price type. What i want to do is have a function so if i select property "Flats" then the price type menu will alter to Per Week.

This is what i have so far but don't know how to go after this?

 
   function doChange() {
 
      var sel = document.forms[0].property_type.selectedIndex;  
 
      if (document.forms[0].property_type[sel].value = "Flat") {
 
      }
 
   }
 

HTML

<form>
<select name="price_type" id="price_type" style="width:120px;">
     <option value="P/M">Let (Per Month)</option>
     <option value="P/W">Let (Per Week)</option>
     <option value="N/A">Buy</option>
    </select>
 
    <select name="property_type" id="property_type" style="width:120px;">
      <option value="">Type</option>
        <option value="Detached">Detached</option>
       <option value="Semi Detached">Semi Detached</option>
        <option value="Terraced">Terraced</option>
        <option value="Flat">Flat</option>
        <option value="Apartment">Apartment</option>
        <option value="Bungalow">Bungalow</option>
        <option value="Dormer Bungalow">Dormer Bungalow</option>
        <option value="Maisonette">Maisonette</option>
    </select>
</form>
 

Cheers,
Adam

[Dormilich]

   function doChange() {
 
// you can use sel as reference to the select element
// would be more clear while reading code
      var sel = document.forms[0].property_type.selectedIndex;  
 
// big mistake here, = is the assignment operator, use ==
      if (document.forms[0].property_type[sel].value = "Flat") {
 
      }
 
   }

some ideas I came up with

   function doChange() 
    {
// good names are half the code …
      var props = document.forms[0].property_type;  
// do the same with the other select
      var price = document.forms[0].price_type;  
 
// if you write incidentally = here, you’ll get an error
// besides that the code is quite explanatory now
      if ("Flat" == props[props.selectedIndex].value) 
      {
           price.selectedIndex = 1;
      }
   }

[adamjblakey]

Thank you very much for your reply, it works a treat :)

[Dormilich]

some additional improvements:

function doChange() 
{
    if ("Flat" == this[this.selectedIndex].value) 
    {
        document.forms[0].price_type.selectedIndex = 1;
    }
}
document.forms[0].property_type.onclick = doChange;