select (HTML element)-CSS Tutorial-php.cn

select (HTML element)

Joseph Gordon-Levitt

Release： 2025-02-26 10:10:08

Original

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<!DOCTYPE html>
<html>
<head>
<title>HTML Select Element</title>
</head>
<body>

<h1>HTML Select Element</h1>

<p>The select form control provides a dropdown menu for user selection.  It allows single or multiple selections depending on the `multiple` attribute.  Styling with CSS can be challenging due to operating system rendering variations.</p>

<img src="/static/imghw/default1.png"  data-src="https://img.php.cn/upload/article/000/000/000/174053581124774.jpg"  class="lazy" alt="select (HTML element) " />

<h2>Example</h2>

<p>A basic select element:</p>

<select id="favoritefood">
  <option value="cheese">Cheese</option>
  <option value="egg">Egg</option>
  <option value="cabbage">Cabbage</option>
</select>


<h2>Use Cases</h2>

<p>Use the select element to present users with a list of choices, conserving space compared to radio buttons.</p>


<h2>Frequently Asked Questions</h2>

<h3>How to create a dropdown list?</h3>

<p>Combine the <code><select></code> element with <code><option></code> elements.  <code><select></code> defines the list, and each <code><option></code> represents a selectable item.  The <code>value</code> attribute specifies the submitted value.</p>

<pre class="brush:php;toolbar:false"><code><select>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>

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How to set a default option?

Use the selected attribute within the <option> element.

<code><select>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes" selected>Mercedes</option>
  <option value="audi">Audi</option>
</select>
</code>

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How to group related options?

Use the <optgroup> element to group options with a common label.

<code><select>
  <optgroup label="Swedish Cars">
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
  </optgroup>
  <optgroup label="German Cars">
    <option value="mercedes">Mercedes</option>
    <option value="audi">Audi</option>
  </optgroup>
</select>
</code>

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How to allow multiple selections?

Add the multiple attribute to the <select> element.

<code><select multiple>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>
</code>

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How to disable an option?

Use the disabled attribute within the <option> element.

<code><select>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes" disabled>Mercedes</option>
  <option value="audi">Audi</option>
</select>
</code>

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How to use in a form?

Enclose the <select> element within <form> tags. The selected value will be submitted with the form.

<code><form>
  <select name="cars">
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="mercedes">Mercedes</option>
    <option value="audi">Audi</option>
  </select>
  <input type="submit">
</form>
</code>

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How to style with CSS?

Style the <select> element using standard CSS techniques. Note that browser and OS differences may affect rendering.

<code>select {
  background-color: yellow;
  color: black;
  border: 1px solid black;
}
</code>

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Can I use without a form?

Yes, but the selected value won't be submitted.

How to handle change events with JavaScript?

Use the onchange event attribute or add an event listener.

<code><select onchange="myFunction(this.value)">
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
</select>

<script>
function myFunction(value) {
  console.log("Selected value: " + value);
}
</script>
</code>

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