References

Beginner-friendly references for web development, with live, editable examples.

The HTML data attribute

Attribute All modern browsers Updated
Quick answer

The HTML data attribute specifies the URL of the resource the object embeds. It is used on the <object> element.

Overview

The data attribute specifies the URL of the resource the object embeds. It applies to the <object> element.

Do not confuse it with the global data-* attributes — this data is the resource URL for <object> only.

Syntax

<object data="file.pdf" type="application/pdf"></object>

Values

Value
A URL pointing to the resource.

Best practices

  • Give every <iframe> a descriptive title.
  • Sandbox untrusted content with sandbox, and avoid combining allow-scripts with allow-same-origin for untrusted sources.
  • Grant only the features a frame needs with the allow attribute.
  • Defer off-screen frames with loading="lazy".

Frequently asked questions

What does the data attribute do?
Sets the URL of an embedded object.
How do I make an iframe secure?
Restrict untrusted content with sandbox, grant minimal features with allow, and never pair allow-scripts with allow-same-origin for untrusted sources.
How do I embed inline HTML in an iframe?
Use the srcdoc attribute to supply the HTML directly instead of a src URL.
Which elements use the data attribute?
It is an element-specific attribute, used on the <iframe>, <object> and <embed> elements.
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