javascript 使用javascript循环选择选项
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for looping on the select options using javascript
提问by Kevin Steve Maningo
Here is my code:
这是我的代码：
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Date Picker</title>
</head>
<body>
<p>Click the button to loop through a block of code five times.</p>
<button onclick="myFunction()">Try it</button>
<select id="demo">
</select>
<p id="demo"></p>
<script>
function myFunction()
{
var i;
for (i=1;i<=5;i++){
document.getElementById("demo").innerHTML="<option value="+i+">"+i+"</option>";
}
}
</script>
</body>
</html>
all I want is when I press the button dropdown box will generate an option like this:
我想要的只是当我按下按钮时下拉框会生成一个这样的选项：
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
but I get only this code
但我只得到这个代码
<option value="5">5</option>
it only show 5 on the option. Please help.. Thank you
它只在选项上显示 5。请帮忙..谢谢
回答by KooiInc
You are overwriting the contents of 'demo' in every iteration. It's better to use DOM methods to add options to a select:
您在每次迭代中都覆盖了“演示”的内容。最好使用 DOM 方法向选择添加选项：
function myFunction(selector)
{
var i;
for (i=1;i<=5;i++){
selector.options[i-1] = new Option(i,i);
}
}
//usage:
myFunction(document.getElementById("demo"));
By the way: check your HTML. The idof elements should be unique. Using your HTML, how can your scripting know which element is meant with document.getElementById("demo")?
顺便说一句：检查您的 HTML。该id元素应该是唯一的。使用您的 HTML，您的脚本如何知道哪个元素与document.getElementById("demo")?
回答by Pranay Rana
Add element to select like this will work for you
像这样添加要选择的元素对您有用
var select = document.getElementById("demo");
var i=0;
for(i=1;i<=5;i++){
select.options[select.options.length] = new Option(i,i);
}
