The HTML selectionStart attribute
Quick answer
The selectionStart is a JavaScript property (not an HTML attribute) of text fields giving (or setting) the character index where the current selection begins.
Overview
The selectionStart attribute start of the text selection (a JS property). It is used on media and form elements — though it is a JavaScript property, not an attribute you write in markup.
Despite appearing in attribute lists, this is a JavaScript IDL property, not an HTML attribute you write in the markup. You read (or set) it on the element in script, for example to inspect playback or selection state.
Syntax
input.selectionStart = 0;\ninput.selectionEnd = input.value.length; // select allValues
| Value |
|---|
| An integer character offset. |
Best practices
- Access it in JavaScript on the element object — there is no corresponding HTML attribute to write.
- Read it to inspect state; some are read-only and cannot be set.
- Do not try to set it as a markup attribute — it will be ignored.
- Combine it with the relevant events to react to changes.
Frequently asked questions
What does the selectionStart attribute do?
Start of the text selection (a JS property).
Can I set this as an HTML attribute?
No. It is a JavaScript property, not a markup attribute. Read or set it on the element in script.
How do I access it?
Through the element object in JavaScript, e.g.
element.property.Which elements use the selectionStart attribute?
It is an element-specific attribute, used on media and form elements — though it is a JavaScript property, not an attribute you write in markup.