Prevent JavaScript function from running twice (setTimeout)

Question

I have this function that runs for several seconds with the use of setTimeout. This function is ran when a button is clicked.

function complete() {
    var div = document.getElementById('log');
    setTimeout(function(){ div.innerHTML = div.innerHTML + intro[Math.floor(Math.random() * intro.length)] + "<br>"; }, 500);
    setTimeout(function(){ div.innerHTML = div.innerHTML + second[Math.floor(Math.random() * second.length)] + "<br>"; }, 2560);
    setTimeout(function(){ div.innerHTML = div.innerHTML + third[Math.floor(Math.random() * third.length)] + "<br>"; }, 4860);
    setTimeout(function(){ div.innerHTML = div.innerHTML + fourth[Math.floor(Math.random() * fourth.length)] + "<br>"; }, 7860);
    setTimeout(function(){ div.innerHTML = div.innerHTML + fifth[Math.floor(Math.random() * fifth.length)] + "<br>"; }, 9640);
}

However, if the user clicks the button multiple times, this function begins to excute multiple times as well. I have tried to prevent this from occuring by using the code below, however, it is not working.

var running;
function complete() {
    if (running == true) { alert('error'); }
    running = true;
    var div = document.getElementById('log');
    setTimeout(function(){ div.innerHTML = div.innerHTML + intro[Math.floor(Math.random() * intro.length)] + "<br>"; }, 500);
    setTimeout(function(){ div.innerHTML = div.innerHTML + second[Math.floor(Math.random() * second.length)] + "<br>"; }, 2560);
    setTimeout(function(){ div.innerHTML = div.innerHTML + third[Math.floor(Math.random() * third.length)] + "<br>"; }, 4860);
    setTimeout(function(){ div.innerHTML = div.innerHTML + fourth[Math.floor(Math.random() * fourth.length)] + "<br>"; }, 7860);
    setTimeout(function(){ div.innerHTML = div.innerHTML + fifth[Math.floor(Math.random() * fifth.length)] + "<br>"; }, 9640);
    running = false;
}

What approach should I take, or how can I fix my code so it can accomplish what I am trying to do?

Answer 1

Your running = false; should be inside timeout function, as timeout will execute asyncronically, the running = false; will execute before your timeout ends

A simple example would be

var running = false,
    div = document.getElementById('response'),
    limit = 5,
    current = 0;

$('#trigger').click(function () {
    if (running === true) {
        alert('Error: The cycle was running. Aborting.');
        running = false;
        return false;
    }
    running = true;
    var end = setInterval(function () {
        if (current >= limit || running == false) {
            running = false;
            clearInterval(end);
        }
        div.innerHTML += 'Hello World<br />';
        current++;
    }, 500);

});

JSFiddle Example