Javascript event doesn't fire when select box options have focus

Question

我正在尝试在选择框选项具有焦点时发生若要发生的事情（写入987654324 @）。从 jsfiddle 代码中，您可以看到我已经让它在事后工作 - 也就是说，一旦选择了选项并将鼠标移回现在关闭的选择框。打开盒子后如何让它工作？

（以防万一，我有另一个函数绑定到同一个元素（选择框），该元素会触发“更改”事件。我想知道这是否是问题所在？）。

HTML：

<div id="Hint"></div>
<div id='select-container'>
    <select name="parent_selection" id="parent_selection">
        <option selected="selected">-- Select 1st option --</option>
        <option value="option1">Option 1</option>
        <option value="option2">Option 2</option>
        <option value="option3">Option 3</option>
    </select>
    <select name="child_selection" id="child_selection">
        <option value="">-- Select 2nd option --</option>
    </select>
</div>

JavaScript：

//Display hint for hovered selection in 1st dropdown
var elSelect_container, elHint; // Declare variables

elAppSelected = document.getElementById('parent_selection');
elHint = document.getElementById('Hint');

function Hint() {
    var elAppSelected = this.options[this.selectedIndex].value;

    if (elAppSelected === 'option1') {
        elHint.innerHTML = 'Good choice';
    }
    if (elAppSelected === 'option2') {
        elHint.innerHTML = 'Better choice';
    }
    if (elAppSelected === 'option3') {
        elHint.innerHTML = 'Best Choice!';
    }
}
    //Create event listener: mouseover calls Hint()
    elAppSelected.addEventListener('mouseover', Hint, false);

http://jsfiddle.net/rpt613/a8hxa1jm/30/

Answer 1

我认为您的问题在于未显示的 onchange 事件。我将 addEventListener 更改为更改 vs mouseover 并且示例工作正常。我不确定你需要另一个 onchange 事件来做什么，但也许你可以将它们结合起来。

JavaScript：

//Display hint for hovered selection in 1st dropdown
var elSelect_container, elHint; // Declare variables

elAppSelected = document.getElementById('parent_selection');
elHint = document.getElementById('Hint');

function Hint() {
    var elAppSelected = this.options[this.selectedIndex].value;

    if (elAppSelected === 'option1') {
        elHint.innerHTML = 'Good choice';
    }
    if (elAppSelected === 'option2') {
        elHint.innerHTML = 'Better choice';
    }
    if (elAppSelected === 'option3') {
        elHint.innerHTML = 'Best Choice!';
    }
}
    //Create event listener: mouseover calls Hint()
    elAppSelected.addEventListener('change', Hint, false);         
  //elAppSelected.addEventListener('mouseover', Hint, false);

http://jsfiddle.net/a8hxa1jm/31/