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function array_intersect_key () {
    // Returns the entries of arr1 that have keys which are present in all the other arguments. Kind of equivalent to array_diff(array_keys($arr1), array_keys($arr2)[,array_keys(...)]). Equivalent of array_intersect_assoc() but does not do compare of the data.  
    // 
    // version: 909.322
    // discuss at: http://phpjs.org/functions/array_intersect_key    // +   original by: Brett Zamir (http://brett-zamir.me)
    // %        note 1: These only output associative arrays (would need to be
    // %        note 1: all numeric and counting from zero to be numeric)
    // *     example 1: $array1 = {a: 'green', b: 'brown', c: 'blue', 0: 'red'}
    // *     example 1: $array2 = {a: 'green', 0: 'yellow', 1: 'red'}    // *     example 1: array_intersect_key($array1, $array2)
    // *     returns 1: {0: 'red', a: 'green'}
    var arr1 = arguments[0], retArr = {};
    var k1 = '', arr = {}, i = 0, k = '';
     arr1keys:
    for (k1 in arr1) {
        arrs:
        for (i=1; i < arguments.length; i++) {
            arr = arguments[i];            for (k in arr) {
                if (k === k1) {
                    if (i === arguments.length-1) {
                        retArr[k1] = arr1[k1];
                    }                    // If the innermost loop always leads at least once to an equal value, continue the loop until done
                    continue arrs;
                }
            }
            // If it reaches here, it wasn't found in at least one array, so try next value            continue arr1keys;
        }
    }
 
    return retArr;}

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$array1 = {a: 'green', b: 'brown', c: 'blue', 0: 'red'}
$array2 = {a: 'green', 0: 'yellow', 1: 'red'}
array_intersect_key($array1, $array2)

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{0: 'red', a: 'green'}