Right-to-left (RTL) · RTL

What it means

On a right-to-left page the text, the reading order and the layout all begin on the right: navigation, the first column and the back arrow sit on the right-hand side. On the web the direction is declared in markup — dir="rtl" on the html element, with a lang attribute naming the language — rather than in CSS, so it holds even when styles do not load¹.

Direction is only the start. Right-to-left pages still carry left-to-right fragments — handles, brand names, tickers, numbers — which must be isolated, so nearly every real right-to-left page is also a page of bidirectional text. The type needs its own settings too: Arabic letters join, so letter-spacing tuned for Latin must go, and the line height must open up for the script's tall ascenders and deep descenders.

Example

An Arabic page declares lang="ar" and dir="rtl" on its html element. A Persian page declares lang="fa" with the same direction, and is built as its own edition rather than as a copy of the Arabic one.

Why it matters to an IB

For an IB whose audience reads Arabic or Persian, a page that renders right-to-left correctly reads as written for them; one that does not reads as translated. The risk warning belongs in the reader's language too. See publishing right-to-left.