--- /dev/null
+<!DOCTYPE html>
+<html>
+<head>
+</head>
+<body>
+
+<script>
+window.addEventListener('load', function(){
+ document.addEventListener('dragenter', function(e){
+ e.preventDefault();
+ },false);
+ document.addEventListener('dragover', function(e){
+ e.preventDefault();
+ // e.dataTransfer.effectAllowed is none
+ e.dataTransfer.dropEffect = 'copy';
+ },false);
+},false);
+</script>
+</html>
\ No newline at end of file