Javascript if statement based on dropdown menu value

Question

I have a question about the if statement in js. I made a statement, but it doesn't seems to work. I want to check these statements from one single click on "button 1". The script is to check if there are any transportation costs before I calculate the total. Can someone tell me how to fix my problem?

Here's my script:

<SCRIPT TYPE="text/javascript">
function berekeningen()
{

if (document.getElementById("DropdownMenu1").value = "Eeklo" && document.getElementById("Order_Subtotal").firstChild.data >= 20)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Adegem" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Kaprijke" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Lembeke" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Oosteeklo" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Sint-Laureins" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Ursel" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Waarschoot" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Zomergem" && document.getElementById("Order_Subtotal").firstChild.data >= 25)
  {
  document.getElementById("Transportation_Cost").value="0.00";
  }
else
  {
  document.getElementById("Transportation_Cost").value="3.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Knesselare")
  {
  document.getElementById("Transportation_Cost").value="5.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Lovendegem")
  {
  document.getElementById("Transportation_Cost").value="5.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Bassevelde")
  {
  document.getElementById("Transportation_Cost").value="5.00";
  }

if  (document.getElementById("DropdownMenu1").value = "Maldegem")
  {
  document.getElementById("Transportation_Cost").value="5.00";
  }
}
</SCRIPT>

Edit: I changed the script a bit with variables but it doesn't work

<script type="text/javascript" src="http://code.jquery.com/jquery-1.8.0.js"></script>

<SCRIPT TYPE="text/javascript">
function berekeningen()
{
   var plaats           = document.getElementById("plaats").value;
   var kosten           = document.getElementById("kosten").value;
   var subtotaal        = document.getElementById("Bestelling_subtotaal").firstChild.data
   var class_1_plaatsen = new Array("Eeklo");
   var class_2_plaatsen = new Array("Adegem", "Kaprijke", "Lembeke", "Oosteeklo",
                                    "Sint-Laureins", "Ursel", "Waarschoot", "Zomergem");
   var class_3_plaatsen = new Array("Knesselare", "Lovendegem", "Bassevelde", "Maldegem");

   if ($.inArray(plaats, class_1_plaatsen) >= 0) {

      // Berekening voor plaatsen in prijscategorie 1 hieronder.

   }
   else if ($.inArray(plaats, class_2_plaatsen) >= 0) {

      // Berekening voor plaatsen in prijscategorie 2 hieronder.

   }
   else {

      // Berekening voor overige plaatsen hieronder.

   }
}
</SCRIPT>

I wan't to make this:

When var plaats = class_1_plaatsen and subtotaal < 15, then alert (We leveren vanaf minimum € 15). But if subtotaal is between 15 and 20, then kosten = 3. But if subtotaal >= 20, then kosten = 0.

When var plaats = class_2_plaatsen and subtotaal < 20, then alert (We leveren vanaf minimum € 20). But if subtotaal is between 20 and 25, then kosten = 3. But if subtotaal >= 25, then kosten = 0.

When var plaats = class_3_plaatsen and subtotaal < 20, then alert (We leveren vanaf minimum € 20). But if subtotaal >= 20, then kosten = 5.

Dyasten

jslint.com, FIY: = is an assignment operator, == comparison, === strict comparison (that's what you should use). — valentinas
– valentinas, Commented Aug 13, 2012 at 23:00

KingKongFrog · Accepted Answer · 2012-08-13 23:00:48Z

1

Shouldn't all your if statements have two ==

if  (document.getElementById("DropdownMenu1").value == "Knesselare")

answered Aug 13, 2012 at 23:00

KingKongFrog

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Comments

limedrop · Accepted Answer · 2012-08-13 23:01:17Z

1

Generally you don't want to use the single = sign in an if statement; it evaluates as a new variable assignment.

Instead of = use == like this:

if (document.getElementById("DropdownMenu1").value == "Eeklo" && document.getElementById("Order_Subtotal").firstChild.data >= 20)

answered Aug 13, 2012 at 23:01

limedrop

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