function AJAX(url) {
	  this.url=url
	}
  
	AJAX.prototype.execCall=function (command,params,sobj,callback) {
	  try {
  	  var ajax = this.getAJAXobject()
      ajax.open('POST', this.url, true);
  	  var code=Math.random()
  	  ajax.onreadystatechange = function() { 
          if (ajax.readyState == 4) {
           if (ajax.status == 200)
           {
             if (callback!=null) {      
               var response = ajax.responseText.parseJSON()
               if (response==null)
               {
                 callback(command,null,sobj,response)
                 return false
               }
               callback(command,response.status,sobj,response.result)   
             }           
           }	  
  	    };	
  	  }
	    var data=new Object();
      data.command=command
      data.request=params
	    var p='data='+encodeURI(data.toJSONString())
      ajax.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      ajax.setRequestHeader("Content-length", p.length);
      ajax.setRequestHeader("Connection", "close");	    
      ajax.send(p);	 
    } catch (e)
    {
      alert (e)
    } 
	}
	
	 AJAX.prototype.getAJAXobject=function() {
      var ajax=null
      if (window.XMLHttpRequest) {
          ajax = new XMLHttpRequest();
      } else if (window.ActiveXObject) {
          try {
              ajax = new ActiveXObject("Msxml2.XMLHTTP");
          } catch (e) {
              try {
                  ajax = new ActiveXObject("Microsoft.XMLHTTP");
              } catch (e) {}
          }
      }	  
      return ajax
	}

// ---------------------

Array.prototype.toJSONString = function () {
    var a = ['['], b, i, l = this.length, v;
    for (i = 0; i < l; i += 1) {
        v = this[i];
        switch (typeof v) {
        case 'undefined':
        case 'function':
        case 'unknown':
            break;
        default:
            if (b) {
                a.push(',');
            }
            a.push(v === null ? "null" : v.toJSONString());
            b = true;
        }
    }
    a.push(']');
    return a.join('');
};

Boolean.prototype.toJSONString = function () {
    return String(this);
};

Date.prototype.toJSONString = function () {

    function f(n) {
        return n < 10 ? '0' + n : n;
    }

    return '"' + this.getFullYear() + '-' +
            f(this.getMonth() + 1) + '-' +
            f(this.getDate()) + 'T' +
            f(this.getHours()) + ':' +
            f(this.getMinutes()) + ':' +
            f(this.getSeconds()) + '"';
};

Number.prototype.toJSONString = function () {
    return isFinite(this) ? String(this) : "null";
};

Object.prototype.toJSONString = function () {
    var a = ['{'], b, i, v;
    for (i in this) {
        if (this.hasOwnProperty(i)) {
            v = this[i];
            switch (typeof v) {
            case 'undefined':
            case 'function':
            case 'unknown':
                break;
            default:
                if (b) {
                    a.push(',');
                }
                a.push(i.toJSONString(), ':',
                        v === null ? "null" : v.toJSONString());
                b = true;
            }
        }
    }
    a.push('}');
    return a.join('');
};

String.prototype.parseJSON = function () {
    try {
        if (/^("(\\.|[^"\\\n\r])*?"|[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t])+?$/.test(this)) {
            return eval('(' + this + ')');
        }
    } catch (e) {
    }
    return null;
};

(function () {
    var m = {
        '\b': '\\b',
        '\t': '\\t',
        '\n': '\\n',
        '\f': '\\f',
        '\r': '\\r',
        '"' : '\\"',
        '\\': '\\\\'
    };

    String.prototype.toJSONString = function () {
        if (/["\\\x00-\x1f]/.test(this)) {
            return '"' + this.replace(/([\x00-\x1f\\"])/g, function(a, b) {
                var c = m[b];
                if (c) {
                    return c;
                }
                c = b.charCodeAt();
                return '\\u00' +
                    Math.floor(c / 16).toString(16) +
                    (c % 16).toString(16);
            }) + '"';
        }
        return '"' + this + '"';
    };

})();