extjs fileUpload下传后返回报错missing } in XML expression

extjs fileUpload上传后返回报错missing } in XML expression
doDecode = function(json) { return eval("(" + json + ")") },?

替换成

doDecode = function(json) {        if(json.indexOf('<pre>') != -1){            json = json.substring(5, json.length-6);            return eval("(" + json + ")");        }        return eval("(" + json + ")")    },