<input type="file" name="file1" onfocus="preview_new(this.value,view1);">
<span id="view1"><img src="preview.gif" alt="미리보기"></span>

<script>
function preview_new(img,obj) {
       if (img.length == 0) return;

       idx = img.lastIndexOf("\\");
       filename = img.substring(idx+1);
       idx2 = filename.lastIndexOf("
.");
       ext = filename.substring(idx2+1);
       ext2 = ext.toLowerCase();

       if ( ext2 == "
jpg" || ext2 == "gif" || ext2 == "jpeg" )
           obj.innerHTML = "
<img src=\"file://" + img + "\" width=200>";
}
</script>