JavaScript实现map

//定义map     
function Map() {
    this.container = {};
}
//将key-value放入map中     
Map.prototype.put = function(key, value) {
    try {
        if (key != null && key != "")
            this.container[key] = value;
    } catch (e) {
        return e;
    }
};

//根据key从map中取出对应的value     
Map.prototype.get = function(key) {
    try {
        return this.container[key];
    } catch (e) {
        return e;
    }
};

//判断map中是否包含指定的key     
Map.prototype.containsKey = function(key) {
    try {
        for ( var p in this.container) {
            if (p == key)
                return true;
        }
        return false;

    } catch (e) {
        return e;
    }

}

//判断map中是否包含指定的value     
Map.prototype.containsValue = function(value) {
    try {
        for ( var p in this.container) {
            if (this.container[p] === value)
                return true;
        }
        return false;

    } catch (e) {
        return e;
    }
};

//删除map中指定的key     
Map.prototype.remove = function(key) {
    try {
        delete this.container[key];
    } catch (e) {
        return e;
    }
};

//清空map     
Map.prototype.clear = function() {
    try {
        delete this.container;
        this.container = {};

    } catch (e) {
        return e;
    }
};

//判断map是否为空     
Map.prototype.isEmpty = function() {

    if (this.keySet().length == 0)
        return true;
    else
        return false;
};

//获取map的大小     
Map.prototype.size = function() {

    return this.keySet().length;
}

//返回map中的key值数组     
Map.prototype.keySet = function() {
    var keys = new Array();
    for ( var p in this.container) {
        keys.push(p);
    }

    return keys;
}

//返回map中的values值数组     
Map.prototype.values = function() {
    var valuesArray = new Array();
    var keys = this.keySet();
    for (var i = 0; i < keys.length; i++) {
        valuesArray.push(this.container[keys[i]]);
    }
    return valuesArray;
}

//返回 map 中的 entrySet 对象
Map.prototype.entrySet = function() {
    var array = new Array();
    var keys = this.keySet();
    for (var i = 0; i < keys.length; i++) {
        array.push(keys[i],this.container[keys[i]]);
    }
    return array;
}

//返回 map 中的 value值的和(当值是 Nunmber 类型时有效)
Map.prototype.sumValues = function() {
    var values = this.values();
    var result = 0;
    for (var i = 0; i < values.length; i++) {
        result += Number(values[i]);
    }
    return result;
}

///计算两个整数的百分比值 
function toPercent(num, total){
    num = parseFloat(num); 
    total = parseFloat(total); 
    if (isNaN(num) || isNaN(total)) { 
        return "0"; 
    } 
    return total <= 0 ? "0%" : (Math.round(num / total * 10000) / 100.00 + "%"); 
//    return (Math.round(this * 10000)/100).toFixed(2) + '%';
}