我使用了以下代码：
var input_element = document.getElementById("Element");
input_element.addEventListener("drop", function (event) {
var types = event.dataTransfer.types;
if (types.length > 2 || types.indexOf("text/plain") === -1)
event.preventDefault();
else{
setTimeout(function(){ input_element.value = ""; },10);
}
}, false);
但是我收到此错误：ForbiddenError：无效的csrf令牌，任何人都可以帮我解决这个问题
{“ readyState”：4，“ responseText”：“ \ n \ n \ n \ n错误\ n \ n \ n
ForbiddenError: invalid csrf token
at csrf (/home/ubuntu/openhab-cloud/node_modules/csurf/index.js:112:19)
at /home/ubuntu/openhab-cloud/app.js:277:9
at Layer.handle [as handle_request] (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:317:13)
at /home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:284:7
at Function.process_params (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:335:12)
at Context.next (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:275:10)
at Context.actions.pass (/home/ubuntu/openhab-cloud/node_modules/passport/lib/passport/context/http/actions.js:77:8)
at SessionStrategy.authenticate (/home/ubuntu/openhab-cloud/node_modules/passport/lib/passport/strategies/session.js:67:10)
at attempt (/home/ubuntu/openhab-cloud/node_modules/passport/lib/passport/middleware/authenticate.js:243:16)
at Passport.authenticate (/home/ubuntu/openhab-cloud/node_modules/passport/lib/passport/middleware/authenticate.js:244:7)
at Layer.handle [as handle_request] (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:317:13)
at /home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:284:7
at Function.process_params (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:335:12)
at next (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:275:10)
at Passport.initialize (/home/ubuntu/openhab-cloud/node_modules/passport/lib/passport/middleware/initialize.js:69:5)
at Layer.handle [as handle_request] (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:317:13)
at /home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:284:7
at Function.process_params (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:335:12)
at next (/home/ubuntu/openhab-cloud/node_modules/express/lib/router/index.js:275:10)