如何在上传前后预览图像?

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我要在表单中预览图像或照片,但它不起作用,HTML代码如下所示:

<form action="" method="post" enctype="multipart/form-data" name="personal_image" id="newHotnessForm">
    <p><label for="image">Upload Image:</label>
    <input type="file" id="imageUpload"/></p>
    <p><button type="submit" class="button">Save</button></p>
        <div id="preview">
            <img width="160px" height="120px" src="profile pic.jpg" id="thumb" />
        </div>
    </form>

并引入了JS代码/脚本:

<script type="text/jaavascript">
$(document).ready(function(){
    var thumb=$('#thumb');
    new AjaxUpload('imageUpload',{
    action:$('newHotnessForm').attr('action'),
    name:'image',
    onSubmit:function(file,extension){
        $('#preview').addClass('loading');
    },
    onComplete:function(file,response){
        thumb.load(function(){
            $('#preview').removeClass('loading');
            thumb.unbind();
        });
        thumb.attr('src',response);
    }
    });
});

为什么图像或图片的预览不起作用?

提问于
用户回答回答于

试试这个:

<script type="text/javascript">
        function readURL(input) {
            if (input.files && input.files[0]) {
                var reader = new FileReader();

                reader.onload = function (e) {
                    $('#blah').attr('src', e.target.result);
                }

                reader.readAsDataURL(input.files[0]);
            }
        }
    </script>

<body>
    <form id="form1" runat="server">
        <input type='file' onchange="readURL(this);" />
        <img id="blah" src="#" alt="your image" />
    </form>
</body>
用户回答回答于

HTML:

<div id="wrapper">
    <input id="fileUpload" type="file" />
    <br />
    <div id="image-holder"></div>
</div> 

jQuery:

$("#fileUpload").on('change', function () {

    var imgPath = $(this)[0].value;
    var extn = imgPath.substring(imgPath.lastIndexOf('.') + 1).toLowerCase();

    if (extn == "gif" || extn == "png" || extn == "jpg" || extn == "jpeg") {
        if (typeof (FileReader) != "undefined") {

            var image_holder = $("#image-holder");
            image_holder.empty();

            var reader = new FileReader();
            reader.onload = function (e) {
                $("<img />", {
                    "src": e.target.result,
                        "class": "thumb-image"
                }).appendTo(image_holder);

            }
            image_holder.show();
            reader.readAsDataURL($(this)[0].files[0]);
        } else {
            alert("This browser does not support FileReader.");
        }
    } else {
        alert("Pls select only images");
    }
});

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