set the value of a variable synchronously for an asynchronous function

function getWords( callback ){

    var words = [];

    chrome.runtime.sendMessage({detail: "words"}, function(response) {
        console.log(response) // prints ["word1, "word2" ..]
        callback(response);
    });

}



function processWords(words){
    //do your logic in here
    console.log(words);
}
getWords(processWords);