Javascript array of strings

so I ran into this strange problem. I have an array status=new Array(). Then I repeat from 0to N-1and assign. status[i]="idle";I tried to give a warning to check the values, and they are all assigned to the coma symbol ,. Does anyone know what happened?

var status=new Array();
window.onload = function() {
    for(var i=0;i<5;i++) {
        status[i]="idle";
        alert(status[i]);
    }
}