Question

I have been trying to do this

function test()
{
    $.getJSON("http://myurl.com",function (data){
        for( i=0; i<data.length; i++){
            test = createElement('img');
            test.onclick = function (){ myotherfun(data[i]); }
        }
    }
}

function myotherfun(data)
{
    alert(data);
}

An error message states that data isn’t covered by the scope.

Can some one explain why this happens?

Answer 1

Now that you’ve edited your question I can see the problem XD

The problem is that the onclick function will use the current values of data and (more importantly) i. So essentially it’s looking for data[data.length], which by the definition of length doesn’t exist.

Instead, you need to “lock” the value of the iterator. Here’s how you can do it:

for(i=0; i<data.length; i++) {
  (function(i) {
    // do stuff that relies on i
  })(i);
}