chrome.runtime.onMessage.addListener(handleMessage); function handleMessage(request, sender, sendResponse) { switch(request.name) { case "highlight-para": highlightPara(); case "show-foo": showFoo(); case "show-confirm": showConfirm(); } } function highlightPara() { } function beastNameToURL(beastName) { switch (beastName) { case "Frog": return chrome.extension.getURL("beasts/frog.jpg"); case "Snake": return chrome.extension.getURL("beasts/snake.jpg"); case "Turtle": return chrome.extension.getURL("beasts/turtle.jpg"); } }