html代码如下：

<div class="file">   <span>上传头像</span>   <input type="file" name="addPic" class="addPic" style="" id="addPic" accept=".jpg, .gif, .png" resetonclick="true" data-nonce="<?php echo $wp_create_nonce; ?>"></div>//其中<?php $wp_create_nonce = wp_create_nonce('wpshequ-'.get_current_user_id());?>

js（使用了JS中的FormData）代码如下：

<script type="text/javascript">  $("#addPic").change(function(e){    var _this = $(this)    var nonce = _this.data("nonce")    var file = e.currentTarget.files[0];    console.log(file)    //结合formData实现图片预览    var sendData=new FormData();    sendData.append('nonce',nonce);    sendData.append('action','update_avatar_photo');    sendData.append('file',file);        $.ajax({      url: "/wp-admin/admin-ajax.php",      type: 'POST',      cache: false,      data: sendData,      processData: false,      contentType: false    }).done(function(res) {      if (res.status == 1) {        layer.msg(res.msg, function(){ location.reload(); });        setTimeout(function(){location.reload()},1000)      }else{        layer.msg(res.msg, function(){ location.reload(); });      }    }).fail(function(res) {        layer.msg('网络错误', function(){ location.reload(); });    });  });</script>//其中的弹窗提示使用了layer.js

php后端处理代码如下：

// 上传头像avatar_photofunction mx_update_avatar_photo(){    header('Content-type:application/json; Charset=utf-8');    global $current_user;    $uid = $current_user->ID;    $nonce   = !empty($_POST['nonce']) ? $_POST['nonce'] : null;    $file = !empty($_FILES['file']) ? $_FILES['file'] : null;    if ($nonce && !wp_verify_nonce($nonce, 'wpshequ-' . $uid)) {        echo json_encode(array('status' => '0', 'msg' => '非法请求'));exit;    }    $file_index = mb_strrpos($file["name"],'.'); //扩展名定位    //图片验证    $is_img = getimagesize($file["tmp_name"]);        if(!$is_img && true){        echo json_encode(array('status' => '0', 'msg' => '上传文件类型错误'));exit;    }    //图片类型验证    $image_type = ['image/jpg', 'image/gif', 'image/png', 'image/bmp', 'image/pjpeg', "image/jpeg"];    if(!in_array($file['type'], $image_type) && true){        echo json_encode(array('status' => '0', 'msg' => '禁止上传非图片类型文件'));exit;    }    //图片后缀验证    $postfix = ['.png','.jpg','.jpeg','pjpeg','gif','bmp'];    $file_postfix = strtolower(mb_substr($file["name"], $file_index));    if(!in_array($file_postfix, $postfix) && true){        echo json_encode(array('status' => '0', 'msg' => '上传后缀不允许'));exit;    }    if ( !empty( $file ) ) {        // 获取上传目录信息        $wp_upload_dir = wp_upload_dir();        // 将上传的图片文件移动到上传目录 md5纯命名图片        $info = pathinfo($file['name']);        $ext  = empty($info['extension']) ? '' : '.' . $info['extension'];        $name = basename($file['name'], $ext);        $basename = time().'-'.substr(md5($name), 0, 15) . $ext;        //        $filename   = $wp_upload_dir['path'] . '/' . $basename;        $re         = rename( $file['tmp_name'], $filename );        $attachment = array(            'guid'           => $wp_upload_dir['url'] . '/' . $basename,            'post_mime_type' => $file['type'],            'post_title'     => preg_replace( '/\.[^.]+$/', '', $basename ),            'post_content'   => '',            'post_status'    => 'inherit'        );        $attach_id  = wp_insert_attachment( $attachment, $filename );        require_once( ABSPATH . 'wp-admin/includes/image.php' );        $attach_data = wp_generate_attachment_metadata( $attach_id, $filename );        wp_update_attachment_metadata( $attach_id, $attach_data );        if($attach_id){            update_user_meta($uid, 'wp_user_avatar', $attach_id);            echo json_encode(array('status' => '1', 'msg' => '上传成功'));exit;        } else {            echo json_encode(array('status' => '0', 'msg' => '上传失败'));exit;        }    }    echo json_encode(array('status' => '0', 'msg' => '文件错误'));exit;}add_action('wp_ajax_mx_update_avatar_photo', 'mx_update_avatar_photo');add_action('wp_ajax_nopriv_mx_update_avatar_photo', 'mx_update_avatar_photo');