php ajax bootstrap多文件上传图片预览，ajax上传文件

<form enctype="multipart/form-data" id="upForm">

    <label class="btn btn-info" for="picture" title="Upload image file" id="uploadImgBtn" class="image_up">

        <input type="file" name="file" multiple class="sr-only" id="picture" accept=".jpg,.jpeg,.png">    

        <span class="docs-tooltip" data-toggle="tooltip" data-animation="false" title="">选择本地图片</span>

    </label>

    <div id="previewImg" class="col-md-5">

    </div>

</form>

$('#picture').on('change', function(){
    #图片预览并上传 
    var imgFiles = $(this)[0].files
    for (i=0;i<imgFiles.length;i++){

        filePath = imgFiles[i].name
        fileFormat = filePath.split('.')[1].toLowerCase()
        src = window.URL.createObjectURL(imgFiles[i])
        if(!fileFormat.match(/png|jpg|jpeg/) ) {
            alert('上传错误,文件格式必须为：png/jpg/jpeg')
            return
        }
        var preview = document.getElementById("previewImg")
        var img = document.createElement('img')
        img.width = 600

        img.src = src
        preview.appendChild(img)

    }
    //多文件
    var formData = new FormData();
    for(var i=0; i<$('#picture')[0].files.length;i++){
        formData.append('file[]', $('#picture')[0].files[i]);
    }
    //单文件

    // var formData = new FormData($('#upForm')[0]);

    //formData.append('file',$(':file')[0].files[0]);

    console.log(formData)
    $.ajax({
        url:'/orc/recognition/upload',
        type: 'POST',
        data: formData,
        //这两个设置项必填
        contentType: false,
        processData: false,
        success:function(data){
            var srcPath = eval("(" + data + ")");
            //注意这里的路径要根据自己的储存文件的路径设置
            if(srcPath.msg != 'true'){
                //alert('未识别的文件');
            }else{
                //$('#image_orc').attr('src', '/' + srcPath.src);
            }
            location.reload();

        }
    })

})

PHP：
public function upload(){

    $upFile = $_FILES['file'];
    var_dump($upFile);

}