请求文件下载URL过长处理

/*
* PostNewWin
* Author:ppchen
*/
var PostNewWin = function(url){
    var urlArr = url.split("?");
    var postUrl = urlArr[0];
    var postData = urlArr[1];
    var iframe = document.getElementById("postData_iframe");
    if(!iframe){
        iframe = document.createElement("iframe");
        iframe.id = "postData_iframe";
        iframe.scr= "about:blank";
        iframe.frameborder = "0";
        iframe.style.width = "0px";
        iframe.style.height = "0px";

        var form = document.createElement("form");
        form.id = "postData_form";
        form.method = "post";
        form.target = "_blank";

        document.body.appendChild(iframe);
        iframe.contentWindow.document.write("<body>" + form.outerHTML + "</body>");
    }
    iframe.contentWindow.document.getElementById("postData_form").innerHTML = "<input name='postData' id='postData' type='text' value='" + postData + "'/>";
    iframe.contentWindow.document.getElementById("postData_form").action = postUrl;
    iframe.contentWindow.document.getElementById("postData_form").submit();
};

/// <summary>
/// 从Form中取得参数
/// Author:ppchen
/// </summary>
/// <returns>参数集合</returns>
private NameValueCollection ParseFormData()
{
    NameValueCollection sQueryString = new NameValueCollection();
    if (this.Request.Form.Count > 0 && this.Request.Form["postData"] != null)
    {
        string sPostData = this.Request.Form["postData"].ToString();
        sPostData = sPostData.Trim(new char[] { '&', ' ' });
        if (!string.IsNullOrEmpty(sPostData))
        {
            string[] sParameterList = sPostData.Split('&');
            for (int i = 0; i < sParameterList.Length; i++)
            {
                string[] sParameter = sParameterList[i].Split('=');
                for (int j = 0; j < sParameter.Length; j = j + 2)
                {
                    sQueryString.Add(sParameter[j], HttpUtility.UrlDecode(sParameter[j + 1]));
                }
            }
        }
    }
    return sQueryString;
}