PHP+JavaScript实现图片预览上传功能开发！

PHP+JavaScript实现图片预览上传功能开发！代码如下：

1、HTML

<div class="id-card">
                <div class="img-up img-front">
                    <img  <if condition="empty($addressInfo['iden_card_positive']) neq true"> src="{$addressInfo['iden_card_positive']}" <else /> src="__VIEW__Public/images/address_ic_id_front.png"</if> id="imgFront" >
                    <input id="front" class="fileImage input" type="file"  accept="image/*">
                </div>
                <div class="img-up img-back">
                    <img  <if condition="empty($addressInfo['iden_card_opposite']) neq true"> src="{$addressInfo['iden_card_opposite']}" <else /> src="__VIEW__Public/images/address_ic_id_back.png"</if> id="imgBack">
                    <input id="back" class="fileImage input2" type="file"  accept="image/*">
                </div>
                <p>点击图片可重新上传</p>
            </div>
<input type="hidden" id="imgPath2" value="{$imgInfo['img_opposite']}" />
    <input type="hidden" id="imgPath1" value="{$imgInfo['img_positive']}" />

2、JavaScript代码

<script>
document.addEventListener('DOMContentLoaded', init, false);
document.addEventListener('DOMContentLoaded', init2, false);

function init() {
var u = new UploadPic();
u.init({
    input: document.querySelector('.input'),
    callback: function (base64) {
         $.ajax({
            url:"__APP__/ImgSets/uploadToImg",