how the code is executed

[runeveryday]

setInterval((function() {
        var index = -1;
        return function() {
            var all = $('#latest a');
            if (index >= 0) {
                all.eq(index).hide();
            }

            index++;
            if (index == all.length) {
                index = 0;
            }

            all.eq(index).show();        
        };
    })(), 1000);

 

how the code is executed?  when index = -1; it not fit the first if condition, then execute    index++;  then which step the code will be executed? if (index >= 0) or  if (index == all.length)  why?

 

 

[nogray]

Your index will always starts at -1 because you defined it as var index = -1; in the begining than your function. Instead, you would need to define the index as a global variable

e.g

var index = -1;
setInterval((function() { 
.... // do not use var index anywhere inside this funciton.