Deleting both values from array if duplicate - JavaScript/jQuery

EDITED with better answer:

var myArr = [1, 1, 2, 5, 5, 7, 8, 9, 9];

function removeDuplicates(arr) {
    var i, tmp;
    for(i=0; i<arr.length; i++) {
        tmp = arr.lastIndexOf(arr[i]);
        if(tmp === i) {
            //Only one of this number
        } else {
            //More than one
            arr.splice(tmp, 1);
            arr.splice(i, 1);
        }
    }
}

Here's my version

var a = [1, 1, 2, 5, 5, 7, 8, 9, 9];

function removeIfduplicate( arr ) {
    var discarded = [];
    var good      = [];
    var test;
    while( test = arr.pop() ) {
        if( arr.indexOf( test ) > -1 ) {
            discarded.push( test );
            continue;
        } else if( discarded.indexOf( test ) == -1 ) {
            good.push( test );
        }
    }
    return good.reverse();
}

x = removeIfduplicate( a );
console.log( x ); //[2, 7, 8]

jsfiddle for this code:

var myArr = [1, 1, 2, 5, 5, 7, 8, 9, 9];
var newArr = myArr;
var h,i,j;


for(h = 0; h < myArr.length; h++) {
    var curItem = myArr[h];
    var foundCount = 0;
    // search array for item
    for(i = 0; i < myArr.length; i++) {
        if (myArr[i] == myArr[h])
            foundCount++;
    }
    if(foundCount > 1) {
        // remove repeated item from new array
        for(j = 0; j < newArr.length; j++) {
            if(newArr[j] == curItem) {                
                newArr.splice(j, 1);
                j--;
            }
        }            
    }
}