function WebService(fn, paramArray, successFn, errorFn)   
{   
    var pagePath = window.location.pathname;   
    //Create list of parameters in the form:   
    //{"paramName1":"paramValue1","paramName2":"paramValue2"}   
    var paramList = '';   
    if (paramArray.length > 0)   
    {   
        for (var i=0; i<paramArray.length; i+=2)   
        {   
            if (paramList.length > 0) paramList += ',';   
                paramList += '"' + paramArray[i] + '":"' + paramArray[i+1] + '"';   
        }   
    }   
    paramList = '{' + paramList + '}';   
    //Call the page method   
    $.ajax({   
        type: "POST",               
        url: "Store.asmx/" + fn,   
        contentType: "application/json; charset=utf-8",   
        data: paramList,   
        dataType: "json",   
        success: successFn,   
        error: errorFn   
    });
}

//                                                                                                    
// From: http://elegantcode.com/2009/02/21/javascript-arrays-via-jquery-ajax-to-an-aspnet-webmethod/  
//                                                                                                    
function WebServiceStringList(fn, list, successFn, errorFn)   
{   
    var jsonText = JSON.stringify({ list: list });    // requires json2.js or json2.min.js
    $.ajax({   
        type: "POST",               
        url: "Store.asmx/" + fn,
        contentType: "application/json; charset=utf-8",   
        data: jsonText,   
        dataType: "json",   
        success: successFn,   
        error: errorFn   
    });    
}