使用jQuery在上传图片之前实现缩略图预览

jQuery代码

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$("#uploadImage").on("change", function(){

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    // Get a reference to the fileList

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    var files = !!this.files ? this.files : [];

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    // If no files were selected, or no FileReader support, return

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    if (!files.length || !window.FileReader) return;

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    // Only proceed if the selected file is an image

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    if (/^image/.test( files[0].type)){

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        // Create a new instance of the FileReader

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        var reader = new FileReader();

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        // Read the local file as a DataURL

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        reader.readAsDataURL(files[0]);

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        // When loaded, set image data as background of div

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        reader.onloadend = function(){

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       $("#uploadPreview").css("background-image", "url("+this.result+")");

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        }

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    }

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});

以下是HTML代码，包含一个显示缩略图的div和一个file input field。

HTML代码

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<div id="uploadPreview"></div>

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<input id="uploadImage" type="file" name="photoimage" class="fimg1" onchange="PreviewImage();" />

为我们的缩略图设置CSSwa 。

CSS代码

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<strong>#uploadPreview {

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    width: 168px;

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    height: 168px;                         

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    background-position: center center;

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    background-size: cover;

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    border: 4px solid #fff;

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    -webkit-box-shadow: 0 0 1px 1px rgba(0, 0, 0, .3);

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    display: inline-block;</strong>