Remove duplicate item from array Javascript [duplicate]

Question

I'm looking for an easy way of removing a duplicate value from an array. I figured out how to detect if there is a duplicate or not, just I don't know how to "push" it from the value. For example, if you go to the link provided, and then type, "abca" (press return/enter key after each letter).. it will alert "duplicate!"

But I also want to figure out how to remove that duplicate from the textarea?

http://jsfiddle.net/P3gpp/

This is the part that seems to not be working ::

sort = sort.push(i);
textVal = sort;
return textVal;

Answer 1

Why do it the hard way, it can be done more easily using javascript filter function which is specifically for this kind of operations:

var arr = ["apple", "bannana", "orange", "apple", "orange"];

arr = arr.filter( function( item, index, inputArray ) {
           return inputArray.indexOf(item) == index;
    });


---------------------
Output: ["apple", "bannana", "orange"]

Answer 2

Based on user2668376 solution, this will return a new array without duplicates.

Array.prototype.removeDuplicates = function () {
    return this.filter(function (item, index, self) {
        return self.indexOf(item) == index;
    });
};

After that you can do:

[1, 3, 3, 7].removeDuplicates();

Result will be; [1, 3, 7].