问题
Good day, sorry for the seemingly broad question title.
I am building an ExtJS4 application using php and sql for the user data. Everything was going fine until one day, I notice this error in my java console:
Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience.
For more help, check http://xhr.spec.whatwg.org/.
Initially, I wasn't that troubled since my application was loading fairly well while testing it in my local network. However, once I uploaded to an online server and tested it, the application loaded really slowly and sometimes it wouldn't load at all.
I don't recall calling an XMLHttpRequest anywhere in my application, so I'm dumbfounded on how or why I'm getting this warning all of a sudden.
The only way I connect to my database and back is via Stores.
Also, as a side question, is there a way to make ExtJS4 applications load faster? I've minimized the size of the images/icons I use and I think the issue lies with the stores but none of my stores are set on autoload.
Any help is very much appreciated. Thank you.
回答1:
I had this error a while a ago. It is caused by Ext.Loader which loads the Ext classes dynamically.
I could solve it by adding the required classes in the Ext.require([...]) statement in the main js file of my application (i.e. app.js).
The docs for Ext.Loader explain when and why asynchronous and synchronous loading happens.
回答2:
Not sure about the main question, never seen that before with extjs 4 apps I have written.
For the question in loading the application faster you should be using sencha CMD to produce a concatenated and minified version of your source for using in a production environment.
Edit
I just came across this SO - "Synchronous XMLHttpRequest on the main thread is deprecated" using nodejs app.get or http-server
Talks about the same issue but with a different framework and comments suggests its an error on client side. Have you changed much lately with how your are fetching data from the server?
来源：https://stackoverflow.com/questions/28524757/extjs-4-2-possible-causes-of-a-sychronous-xmlhttprequest-warning