}
 
         // Test if content can be previewed
-         type = document.getElementById('file_select').files[0].type;
-         if (type.indexOf("image") > -1 ||
-             type.indexOf("audio") > -1 ||
-             type.indexOf("text") > -1 ||
-             type.indexOf("video") > -1)
-         {
+        type = document.getElementById('file_select').files[0].type;
+        if ((type.startsWith('image/')
+                || type.startsWith('audio')
+                || type.startsWith('text/plain')
+                || type.startsWith('video/'))
+            && !type.includes('image/svg+xml'))
+        {
             document.getElementById('preview_link').href = preview_link_href;
             document.getElementById('preview_link_text').innerHTML = web_root + preview_link_href;
             document.getElementById('upload_finished_preview').style.display = '';
-         }
+        }
     }
 
     // Direct download link
     }
 }
 
+function XHRErrorHandler(e)
+{
+    var text = "${e.type}: ${e.loaded} bytes transferred"
+    console.log(text)
+}
+
 function pop_failure (e)
 {
-    var text = "An error occured";
+    var text = "<p>An error occured";
     if (typeof e !== 'undefined')
-        text = e;
-    text = "<p>" + text + "</p>";
+        text += ": " + e;
+    text += "</p>";
     document.getElementById('error_pop').innerHTML = e;
 
     document.getElementById('uploading').style.display = 'none';
         d.setSeconds (d.getSeconds() + 604800);
         return true;
     }
+    if (time == 'fortnight')
+    {
+        d.setSeconds (d.getSeconds() + 1209600);
+        return true;
+    }
     if (time == 'month')
     {
                d.setSeconds (d.getSeconds() + 2592000);
 
     var req = new XMLHttpRequest ();
     req.upload.addEventListener ("progress", upload_progress, false);
-    req.addEventListener ("error", pop_failure, false);
-    req.addEventListener ("abort", pop_failure, false);
+    req.addEventListener ("error", XHRErrorHandler, false);
+    req.addEventListener ("abort", XHRErrorHandler, false);
     req.onreadystatechange = function ()
     {
         if (req.readyState == 4 && req.status == 200)
 
             show_link (res[0], res[1], res[2], expiryDate);
         }
+        else
+        {
+            pop_failure ("<?php echo t("ERR_OCC"); ?>");
+        }
     }
     req.open ("POST", 'script.php' , true);
 
     async_global_time = time;
 
     var req = new XMLHttpRequest ();
-    req.addEventListener ("error", pop_failure, false);
-    req.addEventListener ("abort", pop_failure, false);
+    req.addEventListener ("error", XHRErrorHandler, false);
+    req.addEventListener ("abort", XHRErrorHandler, false);
     req.onreadystatechange = function ()
     {
         if (req.readyState == 4 && req.status == 200)
     }
     var req = new XMLHttpRequest ();
     req.upload.addEventListener ("progress", async_upload_progress, false);
-    req.addEventListener ("error", pop_failure, false);
-    req.addEventListener ("abort", pop_failure, false);
+    req.addEventListener ("error", XHRErrorHandler, false);
+    req.addEventListener ("abort", XHRErrorHandler, false);
     req.onreadystatechange = function ()
     {
         if (req.readyState == 4)
             {
                 var res = req.responseText;
 
-                if (/^Error/.test(res))
+                // This error may be triggered when Jirafeau does not receive any file in POST.
+                // This may be due to bad php configuration where post_max_size is too low
+                // comparing to upload_max_filesize. Let's retry with lower file size.
+                if (res === "Error 23")
+                {
+                    async_global_max_size = Math.max(1, async_global_max_size - 500);
+                    async_upload_push (async_global_last_code);
+                    return;
+                }
+                else if (/^Error/.test(res))
                 {
                     pop_failure (res);
                     return;
                 var code = res[0]
                 async_global_transfered = async_global_transfering;
                 async_upload_push (code);
+                return;
             }
             else
             {
-                if (req.status == 413) // Request Entity Too Large
-                {
-                    // lower async_global_max_size and retry
-                    async_global_max_size = parseInt (async_global_max_size * 0.8);
-                }
+                // lower async_global_max_size and retry
+                // This can occurs in several cases:
+                // - Request Entity Too Large (413) due to server bad configuration relative to PHP configuration
+                // - Server Error (500) which can happen when PHP's `max_execution_time` is too low comparared to sent size
+                async_global_max_size = Math.max(1, parseInt (async_global_max_size * 0.5));
                 async_upload_push (async_global_last_code);
+                return;
             }
         }
     }
 function async_upload_end (code)
 {
     var req = new XMLHttpRequest ();
-    req.addEventListener ("error", pop_failure, false);
-    req.addEventListener ("abort", pop_failure, false);
+    req.addEventListener ("error", XHRErrorHandler, false);
+    req.addEventListener ("abort", XHRErrorHandler, false);
     req.onreadystatechange = function ()
     {
         if (req.readyState == 4 && req.status == 200)
     req.send (form);
 }
 
-function upload (max_size)
+function upload (max_chunk_size)
 {
     var one_time_checkbox = document.getElementById('one_time_download');
     var one_time = one_time_checkbox !== null ? one_time_checkbox.checked : false;
-    if (check_html5_file_api ()
-        && document.getElementById('file_select').files[0].size >= max_size)
+    if (check_html5_file_api ())
     {
         async_upload_start (
-            max_size,
+            max_chunk_size,
             document.getElementById('file_select').files[0],
             document.getElementById('select_time').value,
             document.getElementById('input_key').value,
     // Let's compute the current speed
     var d = new Date();
     var speed = upload_time_estimation_moving_average_speed;
-    if (d.getTime() - upload_time_estimation_transfered_date != 0)
+    if (d.getTime() - upload_time_estimation_transfered_date != 0) {
         speed = (total_transfered_size - upload_time_estimation_transfered_size)
                 / (d.getTime() - upload_time_estimation_transfered_date);
+        speed = Math.max(0, speed);
+    }
     // Let's compute moving average speed on 30 values
     var m = (upload_time_estimation_moving_average_speed * 29 + speed) / 30;
     // Update global values
 function upload_time_estimation_time()
 {
     // Estimate remaining time
-    if (upload_time_estimation_moving_average_speed == 0)
+    if (upload_time_estimation_moving_average_speed <= 0)
         return 0;
     return (upload_time_estimation_total_size - upload_time_estimation_transfered_size)
             / upload_time_estimation_moving_average_speed;
                 copyLinkToClipboard(link_id);});
     }
 }
+
+function set_dark_mode() {
+    let steel_sheet = "<?php echo 'media/' . $cfg['dark_style'] . '/style.css.php'; ?>";
+    let shortcut_icon = "<?php echo 'media/' . $cfg['dark_style'] . '/favicon.ico'; ?>";
+    document.getElementById('stylesheet').href = steel_sheet;
+    document.getElementById('shortcut_icon').href = steel_sheet;
+}
+
+function set_light_mode() {
+    let steel_sheet = "<?php echo 'media/' . $cfg['style'] . '/style.css.php'; ?>";
+    let shortcut_icon = "<?php echo 'media/' . $cfg['style'] . '/favicon.ico'; ?>";
+    document.getElementById('stylesheet').href = steel_sheet;
+    document.getElementById('shortcut_icon').href = steel_sheet;
+}
+
+function color_scheme_preferences() {
+    
+    let dark_mode_steel_sheet = "<?php echo 'media/' . $cfg['dark_style'] . '/style.css.php'; ?>"
+    if (window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches) {
+        set_dark_mode();
+    } else {
+        set_light_mode();
+    }
+
+    // When user change its preference
+    window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', lightMode => {
+        lightMode.matches ? set_dark_mode() : set_light_mode();
+    });
+}
+
 // @license-end