1<!--{ 2 3"title": "this()" 4 5}--> 6 7Reference another property value from the same containing block. 8 9Restricted to referencing properties that don't already reference other properties. 10 11<code>this( *property-name*, *fallback* )</code> 12 13## Parameters 14 15* *`property-name`* Property name 16* *`fallback`* A CSS value 17 18## Returns 19 20The referenced property value, or the fallback if it has not been set. 21 22## Examples 23 24```css 25.foo { 26 width: this( height ); 27 height: 100em; 28} 29``` 30 31******** 32 33```css 34/* The following both fail because they create circular references. */ 35.bar { 36 height: this( width ); 37 width: this( height ); 38} 39``` 40