基于下拉菜单值的 Javascript if 语句
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Javascript if statement based on dropdown menu value
提问by Yasin Palit
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?
我对 js 中的 if 语句有疑问。我发表了声明，但似乎不起作用。我想通过单击“按钮 1”来检查这些语句。脚本是在我计算总数之前检查是否有任何运输成本。有人可以告诉我如何解决我的问题吗？
Here's my script:
这是我的脚本：
<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
编辑：我用变量稍微改变了脚本，但它不起作用
<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:
我不想做这个：
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.
当 var plaats = class_1_plaatsen 并且小计 < 15 时，则警报（我们调整 vanaf 最小值为 15）。但如果小计在 15 到 20 之间，则 kosten = 3。但如果小计 >= 20，则 kosten = 0。
当 var plaats = class_2_plaatsen 并且 subtotal < 20 时，则警报（我们调整 vanaf 最小值为 20）。但如果小计在 20 到 25 之间，则 kosten = 3。但如果小计 >= 25，则 kosten = 0。
当 var plaats = class_3_plaatsen 并且小计 < 20 时，请保持警惕（我们调整 vanaf 最小值为 20）。但如果小计 >= 20，则 kosten = 5。
Dyasten
达斯腾
回答by KingKongFrog
Shouldn't all your if statements have two ==
不应该所有的 if 语句都有两个 ==
if (document.getElementById("DropdownMenu1").value == "Knesselare")
回答by limedrop
Generally you don't want to use the single = sign in an if statement; it evaluates as a new variable assignment.
通常，您不想在 if 语句中使用单个 = 符号；它评估为一个新的变量赋值。
Instead of = use == like this:
而不是 = 使用 == 像这样：
if (document.getElementById("DropdownMenu1").value == "Eeklo" && document.getElementById("Order_Subtotal").firstChild.data >= 20)
