react.dev/cookbook/cb-06-style-prop-value-px.md

id	title	layout	permalink
style-prop-value-px	Shorthand for specifying pixel values in style prop	docs	style-prop-value-px.html

Problem

It's tedious to specify an inline style value by appending your number value with the string "px" each time.

Solution

React actually automatically appends the string "px" for you after your number, so this works:

/** @jsx React.DOM */

var divStyle = {height: 10}; // rendered as "height:10px"
React.renderComponent(<div style={divStyle}>Hello World!</div>, mountNode);

Discussion

See Inline Styles in React for more info.

Sometimes you do want to keep the CSS properties unitless. Here's a list of properties that won't get the automatic "px" suffix:

• fillOpacity
• fontWeight
• lineHeight
• opacity
• orphans
• zIndex
• zoom