neilgee

This plugin adds support for placeholder text in browsers that don’t support this HTML5 feature including Internet Explorer 6.
The plugin just activates the placeholders.js script by James Allardice http://jamesallardice.github.io/Placeholders.js/
There is no further configuration required.
For HTML input elements use the placeholder attribute and add a value, this value is removed when a user inputs the field. http://coolestguidesontheplanet.com/add-a-label-into-a-text-input-field-in-a-html-form/#html5
The script is 4KB and is set to load in the footer and has no library dependencies.
<h3>Usage</h3>
Just activate the plugin which loads the script, their is no further configuration.

Placeholder Text

This plugin adds support for placeholder text in browsers that don't support this HTML5 feature.

Tessa (they/them), AuRise Creative

sevenspark

Contact Form 7 – Dynamic Text Extension

With this great plugin, we were able to easily fulfil a customer's request for an extension. 
Thanks a lot

Great Plugin

Extends Contact Form 7 by adding dynamic form fields that accepts shortcodes to prepopulate form fields with default values and dynamic placeholders.

Placeholder Text vs Contact Form 7 – Dynamic Text Extension