Map In Javascript

/**
 * An ADT of Map. This ADT will do functionality as 

 * the key value ADT.
 *
 * @author  : irfanudin ridho
 * @email   : irfan.ub@gmail.com
 * @date    : December 31, 2010
 * @version : 1.0
 */

/**
 * A constructor service.
 */
function Map(){
    this.key = new Array();
    this.value = new Array();
}

/**
 * A method to add an elements to the Map
 *
 * @param k string, number key element
 * @param v string, number, boolean value element
 */
Map.prototype.add = function(k,v){
    var len = this.key.length;
    this.key[len] = k;
    this.value[len] = v;
};

/**
 * A method to get an element as suitable for the key
 *
 * @param k key of the element
 * @return value as suitable for the key.
 */
Map.prototype.get = function(k){
    var index = 0;
    for(i=0;i<k.length;i++){
        if(this.key[i]==k)
        index = i;
    }
    return this.value[index];
};