javascript - reading in an external local .txt file to load data into an array

Question

I currently have javascript code (please see below) that searches an array for a month/day combination, and if it is found, assigns the name of a .jpg file (which is used for the background image of a page). Instead of hard-coding all of the data in the array, I'd like to be able to create an external .txt file with month/day codes and associated image file names, that could be read and loaded into the array. Thanks for your help!

var ourdates = ['0000','0118','0215','0530','0614','0704','0911','1111','1207']

if (ourdates.indexOf(monthday) != -1)

{
ourimage = "flag";
}

Thanks for your response. I'd like to hardcode the file name in the javascript code, read it (the contents of the file) in, and populate the array, without the need to solicit a file name and/or press a button. Will the FileReader still work, or is there another way? — ThirstForITKnowledge, Apr 28 '16 at 19:18
Again: Do you want to read it from your server, or from the user's computer? If the latter, you have to have a file input. — T.J. Crowder, Apr 29 '16 at 06:23
Thanks for your reply. I want to read the file from the user's computer. — ThirstForITKnowledge, May 02 '16 at 14:17
Then you'll need an `` the user uses to give you permission to access the file via the File API. — T.J. Crowder, May 02 '16 at 14:18

score 0 · Answer 1 · edited May 23 '17 at 12:16

~~If you mean loading it from your server, that's a classic use-case for ajax, frequently combined with JSON:~~

var ourdates = null;

var xhr = new XMLHttpRequest();
xhr.open("GET", "/path/to/your/data");
xhr.onreadystatechange = function() {
    if (xhr.readyState == 4 && xhr.status == 200) {
        ourdates = JSON.parse(xhr.responseText);
        // call something that uses `ourdates`
    }
};
xhr.send(null)

If you mean from the user's computer, my answer here shows how to do that with the File API. Doing that requires an <input type="file"> input (or drag-and-drop event) that the user uses to grant access to the file to your script. You can't read a file from their machine without them specifically giving you access to the file.

javascript - reading in an external local .txt file to load data into an array

1 Answers1