javascript - 拖放图像输入文件并在上传前预览

Question

<分区>

Answer 1

您可以使用一些小的 CSS 技巧来做到这一点。 输入元素接受放置。 我像下面这样更改了您的代码:

CSS

.uploader {
    position:relative; 
    overflow:hidden; 
    width:300px; 
    height:350px;
    background:#f3f3f3; 
    border:2px dashed #e8e8e8;
}

#filePhoto{
    position:absolute;
    width:300px;
    height:400px;
    top:-50px;
    left:0;
    z-index:2;
    opacity:0;
    cursor:pointer;
}

.uploader img{
    position:absolute;
    width:302px;
    height:352px;
    top:-1px;
    left:-1px;
    z-index:1;
    border:none;
}

javascript

var imageLoader = document.getElementById('filePhoto');
imageLoader.addEventListener('change', handleImage, false);

function handleImage(e) {
    var reader = new FileReader();
    reader.onload = function (event) {
        $('.uploader img').attr('src',event.target.result);
    }
    reader.readAsDataURL(e.target.files[0]);
}

// Edit for multiple images
// I didn't try but it should work.
// Also you need write some CSS code to see all images in container properly.
function handleImages(e) {
    $('.uploader img').remove();
    for(var i = 0; i < e.target.files.length; i++){
        var reader = new FileReader();
        reader.onload = function (event) {
            var $img = $('<img/>');
            $img.attr('src', event.target.result);
            $('.uploader').append($img);
        }
        reader.readAsDataURL(e.target.files[i]);
    }
}

html

<div class="uploader" onclick="$('#filePhoto').click()">
    click here or drag here your images for preview and set userprofile_picture data
    <img src=""/>
    <input type="file" name="userprofile_picture"  id="filePhoto" />
</div>

希望对你有所帮助。你可以查看http://jsfiddle.net/ELcf6/4/ , 和其他版本 http://jsfiddle.net/ELcf6/8/