In HTML, you can use the required attribute to set required items. You need to add the "required="required"" style to the input element tag. The required attribute specifies that the input field must be filled in before submission. If this attribute is used, the field is required (or required).
The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.
Required items introduced in HTML5
required attribute
required attribute stipulates that the input field must be filled in before submission.
If this attribute is used, the field is required (or required).
Syntax:
<input required="required">
Features:
Applicable to the following types of tags: text, search, url, telephone, email, password, date pickers, number , checkbox, radio and file.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>required属性</title>
</head>
<body>
<form action="demo-form.php">
Username: <input type="text" name="usrname" required />
<input type="submit" />
</form>
<p>
<strong>注意：</strong> Internet Explorer 9及更早 IE 版本，或 Safari
不支持 input 标签的 required 属性。
</p>
</body>
</html>Effect:
Extension:
form form submission - ignore form validation (novalidate of form form Attributes)
novalidate attribute specifies that the form should not be validated when it is submitted.
If this attribute is used, the form will not validate the form input.
Note: The novalidate attribute applies to:
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