HTML standby Attribute

Introduction

The standby attribute is used with the <object> element. It was originally meant to display a short text message while embedded content (such as a plugin, document, or media file) is loading. Although it is obsolete and not reliably supported in modern browsers, understanding it helps when reading legacy HTML or maintaining older sites.

For new projects, use JavaScript, CSS, and accessible loading indicators instead of relying on standby.

What You’ll Learn

Purpose of standby

The standby attribute was designed to improve perceived performance by showing a message such as “Loading, please wait…” while an embedded <object> fetched its resource. In the era of Flash and other plugins, this gave users feedback that content was on the way.

Today, native HTML elements like <video>, <iframe>, and <img> cover most embedding needs, and loading states are handled with standard UI patterns rather than the standby attribute.

📝 Syntax

Set standby to a plain-text message on <object>:

<object
  data="document.pdf"
  type="application/pdf"
  standby="Loading, please wait...">
  <p>Your browser does not support embedded objects.</p>
</object>

Syntax Rules

• Valid only on <object>.
• Value is a string (the loading message text).
• Works alongside data and type on the same element.
• Fallback content inside <object> shows if embedding fails—separate from standby.
• Obsolete: do not depend on browsers displaying the message.
• IDL property: HTMLObjectElement.standby.

💎 Values

The standby attribute accepts a string value—the text message to display while the object loads:

• standby="Loading, please wait..." — Generic loading hint.
• standby="Video is loading..." — Context-specific message.
• standby="Fetching document..." — PDF or file embed.

<object data="chart.svg" type="image/svg+xml" standby="Loading chart...">
  <p>Chart unavailable.</p>
</object>

How It Works

In theory, the browser would show the standby string in the object’s area until the resource in data finished loading. In practice, modern browsers typically skip this step and either show nothing extra or jump straight to the loaded content or fallback markup.

Applicable Elements

standby vs JavaScript loading UI

Examples Gallery

Legacy standby on object, a modern JavaScript loading pattern, and dynamic object.standby.

<object data="example.svg" type="image/svg+xml" standby="Loading, please wait...">
  <p>Your browser does not support embedded objects.</p>
</object>

<object data="example-video.mp4" type="video/mp4" standby="Video is loading...">
  <p>Your browser does not support embedded videos.</p>
</object>

<div id="loadingMessage" role="status" aria-live="polite">Loading content...</div>
<object id="dynamicObject" data="" type="image/svg+xml"></object>

<script>
  var msg = document.getElementById("loadingMessage");
  var obj = document.getElementById("dynamicObject");
  msg.hidden = false;
  obj.data = "chart.svg";
  obj.addEventListener("load", function () { msg.hidden = true; });
</script>

♿ Accessibility

• Do not rely on standby — Screen readers generally do not announce obsolete standby text.
• Use live regions — Put loading text in an element with role="status" and aria-live="polite".
• Provide fallback content — Meaningful text inside <object> when embedding fails.
• Avoid flicker — Hide loading UI quickly once content is ready.
• Focus management — Do not trap keyboard focus in loading overlays.

💡 Best Practices