FormData in IE 11 not defined

Question

I have the following script to get the file data from a input type of file:

var uploadfiles = $(\"#upFile\").get(0);
var uploadedfiles = uploadfiles.files;

         


        

Answer 1

After checking docmode in IE developer tools it turned out it was reverted to 9 for some reason, had an older meta tag for X-UA-Compatible on my master page which I changed to:

<meta http-equiv="X-UA-Compatible" content="IE=edge">

And FormData had no problems at all.

Answer 2

FormData is not fully supported on IE11.

To be specific: FormData instance does not have method 'set'. You need to use append method instead, as follows:

const formData = new FormData();
formData.append('your_key_name', 'your_value_goes_here');

Setting meta http-equiv to IE=edge will not make 'set' property work and is not needed.

Reference: https://developer.mozilla.org/en-US/docs/Web/API/FormData/append