Javascript algorithm to find elements in array that are not in another array

I'm looking for a good algorithm to get all the elements in one array that are not elements in another array. So given these arrays:

var x = ["a","b","c","t"];
var ​​​​​​​​​y = [​​​​​​​"d","a","t","e","g"];

I want to end up with this array:

var z = ["d","e","g"];

I'm using jquery, so I can take advantage of $.each() and $.inArray(). Here's the solution I've come up with, but it seems like there should be a better way.

// goal is to get rid of values in y if they exist in x
var x = ["a","b","c","t"];
var y = ["d","a","t","e","g"];

var z = [];
$.each(y, function(idx, value){
  if ($.inArray(value,x) == -1) {
    z.push(value);
  }
});
​alert(z);  // should be ["d","e","g"]

Here is the code in action. Any ideas?

in ES6 simply

const a1 = ["a", "b", "c", "t"];
const a2 = ["d", "a", "t", "e", "g"];

console.log( a2.filter(x => !a1.includes(x)) );

(another option is a2.filter(x => a1.indexOf(x)===-1) )

Late answer with the new ECMA5 javascript:

var x = ["a","b","c","t"];
var y = ["d","a","t","e","g"];

myArray = y.filter( function( el ) {
  return x.indexOf( el ) < 0;
});

var z = $.grep(y, function(el){return $.inArray(el, x) == -1}); 

Also, that method name is too short for its own good. I would expect it to mean isElementInArray, not indexOf.

For a demo with objects, see http://jsfiddle.net/xBDz3/6/

Here's an alternative using underscore.js:

function inAButNotInB(A, B) {
  return _.filter(A, function (a) {
    return !_.contains(B, a);
  });
}

I am quite late now but maybe it will be helpful for someone.

If the array is not just a simple array but an array of objects then the following can be used:

var arr1 = [
    {
      "prop1": "value1",
      "prop2": "value2",
    },
    {
      "prop1": "value3",
      "prop2": "value4",
    },
    {
      "prop1": "value5",
      "prop2": "value6",
    },
  ];

var arr2 = ['value1','value3', 'newValue'];

// finds all the elements of arr2 that are not in arr1
arr2.filter( 
    val => !arr1.find( arr1Obj => arr1Obj.prop1 === val)
); // outputs "newValue"