exchange=gemw is the parameter/variable used in the Infobox Item template to automatically add the Grand Exchange Market Watch price plus an update link in the infobox for the item. Setting the "exchange" parameter to "gemw" also automatically add a link to Jagex's Grand Exchange Database for quick reference. In addition to that, the image for that item is displayed at the bottom of the infobox. For an example of this parameter being used, see the Bones article. To view the actual coding and documentation, see Template:Infobox Item.
exchange=gemw is the parameter/variable used in the Infobox Item template to automatically add the Grand Exchange Market Watch price plus an update link in the infobox for the item. Setting the "exchange" parameter to "gemw" also automatically add a link to Jagex's Grand Exchange Database for quick reference. In addition to that, the image for that item is displayed at the bottom of the infobox. For an example of this parameter being used, see the Bones article. To view the actual coding and documentation, see Template:Infobox Item.