form表单，上传图片及展示

.comment_con .file{position: relative;top:2rem;z-index: 999;width: 5rem;height: 5rem;background: red;opacity: 0}.comment_con .upload{width: 5rem;height: 5rem;font-size: 4em;font-weight:lighter;line-height: 5rem;text-align: center;position: relative;top:-3rem;z-index: -1;background: #dfdbdc;}.show img{width: 46%;height: 5rem;margin: 0.3rem;}
<form action="" enctype="multipart/form-data">　　<div class="show"><!-- <img src="" > -->　　</div>　　<div>　　　　<input type="file" name="file" class="file" id="file" onchange="changepic(this)">　　　　<div style="" class="upload">+</div>　　</div></form>
<script>var show=document.querySelector(‘.show‘)var show_img=show.getElementsByTagName(‘img‘)[0]function changepic(obj) { ???var newsrc=getObjectURL(obj.files[0]); ???var img=document.createElement(‘img‘) ???show.appendChild(img) ???img.src=newsrc ???????}function getObjectURL(file) { ???????????var url = null ; ???????????if (window.createObjectURL!=undefined) { ????????????????url = window.createObjectURL(file) ; ???????????} else if (window.URL!=undefined) { ????????????????url = window.URL.createObjectURL(file) ; ???????????} else if (window.webkitURL!=undefined) { ????????????????url = window.webkitURL.createObjectURL(file) ; ???????????} ???????????return url ; ??????}</script> ????????