How to check if a file exists in javascript?

问题

I'm using the jquery library to load the content of an html file. Something like this:

$("#Main").load("login.html")

If the file (in this case 'login.html') does not exist, I would like to detect it so that I can redirect the user to an error page for example. Any ideas how I can detect if the file to load exists or not?

回答1:

You can use the ajaxComplete event, whis gives you access to the xhr object which you can query the status of the request e.g a status of 404 will mean the file does not exist.

More Info in the docs http://docs.jquery.com/Ajax/ajaxComplete#callback

Test here http://pastebin.me/48f32a74927bb

e.g

$("#someDivId").ajaxComplete(function(request, settings){
    if (settings.status===404){
        //redirect here
    }
});

回答2:

@PConroy's solution works, but it does the same thing for all failed ajax requests.

If you need this on a per request basis - i.e. if the first request fails it goes to X page and if the second fails go to Y, then you need to do this using the error handle in the $.ajax function:

http://jsbin.com/iwume

(to edit: http://jsbin.com/iwume/edit)

来源：https://stackoverflow.com/questions/197228/how-to-check-if-a-file-exists-in-javascript