如何检查从HTML下拉列表中选择的项目? [英] How to check if an item is selected from an HTML drop down list?
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问题描述
我有一个丢弃的淹没列表,我无法检查是否从下拉列表中选择了一个值
I have a drop drown list and I am having trouble checking whether or not a value has been selected from the drop down list
以下是我的HTML代码: / p>
Below is my HTML Code :
<label class="paylabel" for="cardtype">Card Type:</label>
<select id="cardtype" name="cards">
<option value="selectcard">--- Please select ---</option>
<option value="mastercard">Mastercard</option>
<option value="maestro">Maestro</option>
<option value="solo">Solo (UK only)</option>
<option value="visaelectron">Visa Electron</option>
<option value="visadebit">Visa Debit</option>
</select><br/>
以下是我的JavaScript代码:
Below is my JavaScript Code :
var card = document.getElementByName("cards")[0].value;
if (card.value == selectcard) {
alert("Please select a card type");
}
推荐答案
你错过了引号您的字符串 selectcard
应该是selectcard
Well you missed quotation mark around your string selectcard
it should be "selectcard"
if (card.value == selectcard)
应该是
if (card.value == "selectcard")
这是完整的代码
function validate()
{
var ddl = document.getElementById("cardtype");
var selectedValue = ddl.options[ddl.selectedIndex].value;
if (selectedValue == "selectcard")
{
alert("Please select a card type");
}
}
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