HTML Guide

The for attribute on a label element can’t be an empty string. This attribute is intended to specify which form element a label is associated with, and it must reference the ID of an existing form element. An empty string is neither a valid ID nor a meaningful association.

Explanation

• Invalid HTML: <label for=""></label>

The for attribute expects the value to be the ID of a form element, such as an input, textarea, select, etc.

How to Fix

1. Identify the Form Element: Find the form element (input, textarea, select, etc.) that the label is supposed to be associated with.
2. Assign an ID to the Form Element: Ensure the form element has a unique ID.
3. Modify the Label’s for Attribute: Set the for attribute of the label to match the ID of the form element.

Example

Before Fix

<form>
    <label for="">Username:</label>
    <input type="text" name="username">
</form>

After Fix

<form>
    <label for="username">Username:</label>
    <input type="text" id="username" name="username">
</form>

<label> tags are used to label inputs in form, which need to be present and visible in the document, for example:

<label for="age">Age</label>
<input id="age" />

The id attribute of an HTML element, used to identify the element when linking, scripting or styling, must be unique in the whole document and must not contain whitespace.

Technically, in HTML5, the value for an id attribute may contain any character, except whitespace characters. However, to avoid inadvertent errors, only ASCII letters, digits, _, and - should be used and the value for an id attribute should start with a letter.

When nesting an input element inside a label that has a for attribute, the id attribute of the input is required to match it.

The label element represents a caption in a user interface. The caption can be associated with a specific form control, known as the label element’s labeled control, either using the for attribute, or by putting the form control inside the label element itself.

When the input is inside the label, there’s no need to specify a for attribute as there can only be one input, as in this example:

<label>
  Age
  <input type="text" name="age">
</label>

However, if the for attribute is specified, then it must match the id of the input like this:

<label for="user_age">
  Age
  <input type="text" name="age" id="user_age">
</label>

When nesting a select element inside a label that has a for attribute, the id attribute of the select is required to match it.

The label element represents a caption in a user interface. The caption can be associated with a specific form control, known as the label element’s labeled control, either using the for attribute, or by putting the form control inside the label element itself.

When the select is inside the label, there’s no need to specify a for attribute as there can only be one select, as in this example:

<label>
  Age
  <select>
    <option>young</option>
    <option>old</option>
  </select>
</label>

However, if the for attribute is specified, then it must match the id of the select like this:

<label for="age">
  Age
  <select id="age">
    <option>young</option>
    <option>old</option>
  </select>
</label>

The id attribute is used to identify a single element within a document, it’s not required, but if used it must be unique, and must not be an empty string.

IDs for HTML elements can’t be blank.

A <pattern> element has been found with an invalid ID. Check the format of the ID and ensure it does not start with a digit, full stop (.) or hyphen (-).

The <pattern> element is used within <svg> elements, which use XML 1.0 syntax. That syntax specifies that valid IDs only include designated characters (letters, digits, and a few punctuation marks), and do not start with a digit, a full stop (.) character, or a hyphen-minus (-) character.

The id attribute is used to identify a single element within a document, and is required to be unique. Check the document for repeated IDs.

Drop-down lists can be defined in HTML by using the <select> tag, containing the different <option>s. Each <option> must have a name, which can be either contained between <option> and </option>, or alternatively using the label attribute.

Example:

<select name="size">
  <option value="s">small</option>
  <option value="m" label="medium"></option>
</select>