mobile web – input type=”file” capture image upload then delete the temporary image on memory

I have an issue, that needs your help!!
(sorry for my bad English skills.. but trying to do the best !)

I build a page for fileUpload by in mobile web browser.
it works fine, but ..

there is an issue, for security.
it might happens all browsers, just now I’ve heard, it detected it on IOS safari.

problem is when user take a picture and then finished the upload then
the tester dumped the memory of browser.
and try to restore it to the picture what user uploaded.

it… restored!! ?!?!?!
it’s a secure issue ..

I want solve this problem… want reset or delete memory for read or upload the file …

I hope you understand what I trying to say TT_TT

$("input[type=file]").on("change", function(e){
  var reader = new FileReader();
  reader.addEventListener("load", readFileUplad);
  reader.addEventListener("loaded", function(ev){
     e = null;
     ev = null; 
     reader = null;
     $("input[type=file]").val('');
     $("input[type=file]").closet('form').get(0).reset();    
  });
  reader.readAsDataUrl(e.target.files[0]);
});

function readFileUplad(e){
  var data = new FormData();
  data.append("file", e.target.result);
  data.append("filename", "test.jpg");
  $.ajax({
     cache : false;
     ...
     complate : function(){
        data = null;
     }
  });
}