javascript 预览图片上传

Posted 2021-05-03

// HTML ----------------------------
<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.3/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.3/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->

<div class="container">
	<div class="row">
		<h3 class="text-center">Preview an image before it is uploaded</h3>
		<hr />
		
		<div class="col-md-4 col-md-offset-4">
		    <div class="form-group">
              <div class="main-img-preview">
                <img class="thumbnail img-preview" src="http://farm4.static.flickr.com/3316/3546531954_eef60a3d37.jpg" title="Preview Logo">
              </div>
              <div class="input-group">
                <input id="fakeUploadLogo" class="form-control fake-shadow" placeholder="Choose File" disabled="disabled">
                <div class="input-group-btn">
                  <div class="fileUpload btn btn-danger fake-shadow">
                    <span><i class="glyphicon glyphicon-upload"></i> Upload Logo</span>
                    <input id="logo-id" name="logo" type="file" class="attachment_upload">
                  </div>
                </div>
              </div>
              <p class="help-block">* Upload your company logo.</p>
            </div>
		</div>
	</div>
</div>


// CSS -----------------------------
.form-control, .thumbnail {
    border-radius: 2px;
}
.btn-danger {
    background-color: #B73333;
}

/* File Upload */
.fake-shadow {
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}
.fileUpload {
    position: relative;
    overflow: hidden;
}
.fileUpload #logo-id {
    position: absolute;
    top: 0;
    right: 0;
    margin: 0;
    padding: 0;
    font-size: 33px;
    cursor: pointer;
    opacity: 0;
    filter: alpha(opacity=0);
}
.img-preview {
    max-width: 100%;
}




$(document).ready(function() {
    var brand = document.getElementById('logo-id');
    brand.className = 'attachment_upload';
    brand.onchange = function() {
        document.getElementById('fakeUploadLogo').value = this.value.substring(12);
    };

    // Source: http://stackoverflow.com/a/4459419/6396981
    function readURL(input) {
        if (input.files && input.files[0]) {
            var reader = new FileReader();
            
            reader.onload = function(e) {
                $('.img-preview').attr('src', e.target.result);
            };
            reader.readAsDataURL(input.files[0]);
        }
    }
    $("#logo-id").change(function() {
        readURL(this);
    });
});