注意：以下代码只适用于chrome、Firefox和IE10以上
<!DOCTYPE html><html><head><meta charset="utf-8"><title>Js实现input上传图片时显示缩略图</title></head><input type="file" id="imgFile" /><br /><br /><img src="" height="50" /><body></body></html><script>document.getElementById('imgFile').onchange = function(){var preview = document.querySelector("img");var file = document.querySelector("input[type=file]").files[0];var reader = new FileReader();if(file){reader.readAsDataURL(file);}else{preview.src = '';}reader.onloadend = function(){preview.src = reader.result;}}</script>
