How to set the default value of HTML select drop-down box?-HTML Tutorial-php.cn

How to set the default value of HTML select drop-down box?

醉折花枝作酒筹

Release： 2021-04-26 11:47:28

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This article introduces how to set the default value of the select drop-down box. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

How to set the default value of HTML select drop-down box?

We can set the default value of the select element using the "selected" attribute on the desired option, which is a boolean attribute.

By default, the option tag with the "selected" attribute will be displayed in the drop-down list select tag.

Syntax:

<option value="value" selected>选项名称</option>

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Example 1: Using the selected attribute

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>设置select元素的默认值</title>
	</head>
	<body style = "text-align:center;">  
	    <b>如何设置select元素的默认值？</b> 
	    <p>默认情况下，显示第一个option选项</p> 
	    <select name="plan" id="plan"> 
	        <option value="free">Free</option> 
	        <option value="starter">Starter </option> 
	        <option value="professional">Professional</option> 
	        <option value="corporate">Corporate</option> 
	    </select> 
	    <p>设置Professional选项为默认值</p> 
	    <select name="plan" id="plan"> 
	        <option value="free">Free</option> 
	        <option value="starter">Starter </option> 
	        <option value="professional" selected>Professional</option> 
	        <option value="corporate">Corporate</option> 
	    </select> 
	</body> 
  
</html>

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Rendering:

How to set the default value of HTML select drop-down box?

Example 2: Add a message like "Please select an option" to the list. This option has hidden and disabled properties in addition to checked.

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>设置select元素的默认值</title>
</head>
<body style = "text-align:center;">  
    <p>设置select选项框的默认值</p> 
    <select name="plan" id="plan"> 
        <option value="none" selected disabled hidden>请选择选项</option> 
        <option value="free">Free</option> 
        <option value="starter">Starter </option> 
        <option value="professional">Professional</option> 
        <option value="corporate">Corporate</option> 
    </select>
</body> 
  
</html>

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Rendering:

How to set the default value of HTML select drop-down box?

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