ajaxFileUpload插件上传文件 返回 syntaxError :unexpected token

Html 代码
<table id="deploy_application" class="bordered-table">
<tr>
<td id="application_file">
<input id="file_field" type="file" name="application" size="20" />
</td>
<td id="application_submit">
<input id="submit_button" type="submit" value="Upload" onclick="uploadFile()" />
</td>
</tr>
</table>

function ajaxFileUpload() {
$.ajaxFileUpload
(
{
url: '/upload',
secureuri: false,
fileElementId: 'file_field',
dataType: 'json', //这里选择了json

success: function (data, status) {
alert(data);
},

error: function (data, status, e) {
alert(e);
}
}
)
}

function ajaxFileUpload() {

$.ajaxFileUpload
(
{
url: '/upload',
secureuri: false,
fileElementId: 'file_field',
dataType: 'content', //这里修改为content

success: function (data, status) {
alert(data);
},

error: function (data, status, e) {
alert(e);
}
}
)
}

uploadHttpData: function( r, type ) {
var data = !type;
data = type == "xml" || data ? r.responseXML : r.responseText;
// If the type is "script", eval it in global context
if ( type == "script" )
jQuery.globalEval( data );
// Get the JavaScript object, if JSON is used.
if ( type == "json" ) {
////////////以下为新增代码///////////////
data = r.responseText;
var start = data.indexOf(">");
if(start != -1) {
var end = data.indexOf("<", start + 1);
if(end != -1) {
data = data.substring(start + 1, end);
}
}
///////////以上为新增代码///////////////
eval( "data = " + data);
}
// evaluate scripts within html
if ( type == "html" )
jQuery("<div>").html(data).evalScripts();

return data;
}