使用 HTML select 下拉列表更新 iframe 的 src 路径

Question

I am trying to use a HTML form element (specifically a select dropdown) to update the URL path of an iframe that is embedded on the page. 这应该在每次做出不同的选择时重新加载 iframe。

我已经尝试使用 Javascript function 来传递 select 的值，当 onkeyup 或 onmouseup 事件发生时，我没有看到任何变化：

<!DOCTYPE html>

<head>

<style>

* {font-family: arial;}

</style>
<script type="text/javascript">

window.onload = function() {
  document.monthyear.onkeyup = my;
  document.monthyear.onmouseup = my;

};

function my() {

var my = String(document.monthyear.value);

document.getElementById("iframe").src = my;

};

</script>

</head>

<body>

<select name="monthyear">
    <option value="/258001">
        January 2019
    </option>
    <option value="/258002">
        February 2019
    </option>
    <option value="/258003">
        March 2019
    </option>
    <option value="/258004">
        April 2019
    </option>
</select>

<h1>Month</h1><iframe allowfullscreen frameborder="0" height="450" id="iframe" src="https://www.example.com/258001" style="border:0" width="800"></iframe>

Answer 1

尝试像这样使用：

 <select onchange='this.options[this.selectedIndex].value && (window.location = this.options[this.selectedIndex].value);'>
  <a href='#'><option>choose an action</option></a>
  <option value='Url or div'>Option 1</option>
  <option value='Url or div'>Option 2</option>

  </select>

Answer 2

使用selected属性设置 select 标记的默认值，然后（参见代码中的注释）...

<script>
const select = document.querySelector('#select')
window.onload = function() {
  // set the iframe value to default select value
  document.getElementById("iframe").src = '/258001'
};
// add an event listener that listens for a change to the input and sets the iframe path.
select.addEventListener('change', (e) => {
 document.getElementById("iframe").src = e.target.value
document.getElementById("iframe").contentWindow.location.reload()
})

</script>

</head>

<body>

<select id="select" name="monthyear">
    <option value="/258001" selected="selected">
        January 2019
    </option>
    <option value="/258002">
        February 2019
    </option>
    <option value="/258003">
        March 2019
    </option>
    <option value="/258004">
        April 2019
    </option>
</select>

<h1>Month</h1><iframe allowfullscreen frameborder="0" height="450" id="iframe" src="https://www.example.com/258001" style="border:0" width="800"></iframe>