Loop through an array with a callback function for each iteration.
function loop(array, fn) {
for (var i = 0; i < array.length; i++) {
if (fn.call(array, array[i], i) === false) {
break;
}
}
}
// EXAMPLE
var arr = ['12', '34', '56'];
loop(arr, function (item, index) {
//console.log(this.length);
console.log(item + ' - ' + index);
});