Simple Doubt in Javascript

Question

Well my doubt is relatively simple, I would like to know how would do in Javascript that if a real condition, for example, 2 > 1 instead of the image of img appeared the image of the code in script.

My code:

if(2>1){ document.getElementById("amarelo5").src = "cores-roleta/amarelo1.png";

}

<img id="amarelo5" src="cores-roleta/amarelo0.png">

Answer 1

The problem is that your script is running before the page is finished loading, so run only when finished do this:

window.onload = function() {
    if(2>1){ 
        document.getElementById("amarelo5").src = "cores-roleta/amarelo1.png";
    }
}

Example changing the color of label every 5 seconds, adapt according to your needs. The function to keep calling every time is the setInterval and you report in milliseconds.

var cores = ['red', 'blue', 'green'];
var contador = 0;
window.onload = function() {
    setInterval(function () {
        document.getElementById('tst').style.color = cores[contador % cores.length];
        contador++;
    }, 5000); // 5 segundos
}

<label id="tst">Exemplo cores</label>