使用文件输入选择在php中上传和查看没有表单帖子的图片

<div id="back" style=" background-repeat:no-repeat;  border:thin solid black;     width:200px; height:230px;" >
<input type="file" id="image_file" name="image_file[]" multiple     onchange="fileSelected();" />
<output id="list"></output>

function fileSelected() {
    // get selected file element
    var oFile = document.getElementById('image_file').files[0];

    // filter for image files
    var rFilter = /^(image\/bmp|image\/gif|image\/jpeg|image\/png|image\/tiff)$/i;
    if (! rFilter.test(oFile.type)) {
        document.getElementById('list').style.display = 'block';
        return;
    }


    // get preview element
    var oImage = document.getElementById('back');

    // prepare HTML5 FileReader
    var oReader = new FileReader();

    oReader.onload = function(e){

        // e.target.result contains the DataURL which we will use as a source of the image
        oImage.style.backgroundImage = e.target.result;

        oImage.onload = function () { // binding onload event

            // we are going to display some custom image information here
            sResultFileSize = bytesToSize(oFile.size);
            document.getElementById('list').style.display = 'block';
            document.getElementById('list').innerHTML = 'Name: ' + oFile.name;
        };
    };

    // read selected file as DataURL
    oReader.readAsDataURL(oFile);
}

I want to set the background of the div according to file select, but I am unable to achieve that.

I'm able to do this with an img element but that's not my requirement.

I want to change the div background every time I select a img using file input.

thanx in advance...plz help