What does Dojo consider a XHR request error?

问题

When doing AJAX through Dojo we can pass two callbacks, one to execute after a successfull request and one to execute after an error:

dojo.xhr("GET",{
    url: myURL,
    content: messageContents,
    load: function(returnData, ioArgs){
        //This is called on success
    },
    error: function(returnData, ioArgs){
        //This is called on failure
    }
});

I couldn't find in the documentation what is defined as an error. I'd guess anything with a return code >= 400 but I'm not sure.

回答1:

Generally speaking, an unsuccessful HTTP response code. The determination is made by calling dojo._isDocumentOk which as you'll see basically accepts 2xx and 304 plus some browser-quirk stuff.

来源：https://stackoverflow.com/questions/5721949/what-does-dojo-consider-a-xhr-request-error