客户端异步取服务端数据

1.js可跨域

convertServer={
requestByScript: function(scriptId, dataHref, callback, charset, retry) {
        var isReady = false;
        if (callback) {
            if (typeof (callback) == "string") {
                charset = callback;
                callback = null;
            }
        }
        var head = document.getElementsByTagName("head")[0];
        var objScript = document.getElementById(scriptId);
        if (objScript && !document.all) {
            objScript.src = "";
            objScript.parentNode.removeChild(objScript);
            objScript = null;
        }
        if (objScript != null) {
            if (dataHref.indexOf("?") == -1) dataHref += "?";
            dataHref += "&" + Math.random();
            objScript.src = dataHref;
            var dataScript = objScript;
        } else {
            var dataScript = document.createElement("script");
            dataScript.id = scriptId;
            if (charset) {
                dataScript.charset = charset;
            } else {
                dataScript.charset = "GB2312";
            }
            dataScript.src = dataHref;
            dataScript.defer = true;
            dataScript.type = "text/javascript";
            head.appendChild(dataScript);
        }
        if (document.all) {
            dataScript.onreadystatechange = function() {
                if (dataScript.readyState == "loaded" || dataScript.readyState == "complete") {
                    isReady = true;
                    if (callback) callback();
                }
            }
        } else {
            dataScript.onload = function() {
                isReady = true;
                if (callback) callback();
            }
        }

        if (retry) {
            setTimeout(function() {
                if (retry.times > 0 && !isReady) {
                    retry.times--;
                    if (dataHref.indexOf("?") == -1) dataHref += "?";
                    dataHref += "&" + Math.random();
                    convertServer.requestByScript(scriptId, dataHref, callback, charset, retry);
                }
            }, retry.timeout);
        }
    },
    requestData:function(url,callBack)
    {
        var scriptId="jsReuest"+ Math.random();            
        convertServer.requestByScript(scriptId, url, callBack)         
    }

}

2. jQuery.ajax(options),不能跨域