static/ext/src/util/AbstractMixedCollection.js
function(fn, scope){
        var items = Ext.Array.push([], this.items), // each safe for removal
            i = 0,
            len = items.length,
            item;

        for (; i < len; i++) {
            item = items[i];
            if (fn.call(scope || item, item, i, len) === false) {
                break;
            }
        }
    }
function(fn, scope){
        var items = Ext.Array.push([], this.items), // each safe for removal
            i = 0,
            len = items.length,
            item;

        for (; i < len; i++) {
            item = items[i];
            if (fn.call(scope || item, item, i, len) === false) {
                break;
            }
        }
    }
Executes the specified function once for every item in the collection.
The function should return a boolean value.
Returning false from the function will stop the iteration.

@param {Function} fn The function to execute for each item.
@param {Mixed} fn.item The collection item.
@param {Number} fn.index The index of item.
@param {Number} fn.len Total length of collection.
@param {Object} scope (optional) The scope (<code>this</code> reference)
in which the function is executed. Defaults to the current item in the iteration.

@since Ext 1