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js实现图片上传预览及进度圆圈

js实现图片上传预览及进度圆圈

作者: 曼巴童鞋 | 来源:发表于2017-08-11 17:34 被阅读0次

    完整案例下载地址

    最近在做图片上传的时候,上网找了比较久还没有现成的,因此自己做了一个,实现的功能如下:

    1.去除<input type="file">默认的样式;

    2.使用上传可以查看上传进度(本博做的是上传的百分比,做成进度圆圈类似);

    3.图片从本地选择上传后预览图片;

    首先是去除浏览器默认上传图片框,通过设置css样式可以简单的修改成想要的效果。

    index.html代码如下;

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Document</title>
        <style type="text/css">
            body{
                text-align: center;
            }
            .uploadWrap{
                margin: auto;
                width: 500px;
                height: 500px;
            }
            #li_idCard{
                    width: 210px;
                    height: 120px;
                    background: #b3dde2;
                    color: #fff;
                    text-align: center;
                    line-height: 120px;
                    font-size: 30px;
                    border: 1px solid #999;
                    position: relative;
                    }
            #IDCardFront{
                    width: 210px;
                    height: 120px;
                    opacity: 0;
                    position: absolute;
                    right: 0;
                    top: 0;
                    cursor: pointer;
                    }
            .process {
                width: 280px;
                height: 140px;
                position: absolute;
                top: 30%;
                left: 40%;
                display: none;
            }
            #img{
                margin: 0 auto;
                margin-top: 200px;
            }
        </style>
    </head>
    <body>
        <div class='uploadWrap'>
                <div class="uploadIDcard">
                    <div class="upload_box">
                        <ul>
                            <li id='li_idCard'>
                                <span class="percent" id="percent1">+</span>
                                <canvas class="process" id="process1">0%</canvas>
                                <input type="file" id="IDCardFront" name="IDCardFront">
                                <img id='img' src="">
                            </li>
                            
                        </ul>
                    </div>
                </div>
                
            </div>
    </body>
    <script type="text/javascript" src="jquery.min.js"></script>
    <script type="text/javascript" src="jquery.form.js"></script>
    </html>
    

    这里html代码引入外部js文件。

    js代码

    <script>
    
        //进度条渲染效果
    function drawProcess(id) {
        var text = $("#" + id).text();
        var process = text.substring(0, text.length - 1);
        var canvas = $("#" + id);
        var context = canvas[0].getContext('2d');
        context.clearRect(0, 0, 48, 48);
        context.beginPath();
        context.moveTo(240, 240);
        context.arc(24, 24, 24, 0, Math.PI * 2, false);
        context.closePath();
        context.fillStyle = '#fff';
        context.fill();
        context.beginPath();
        context.moveTo(24, 24);
        context.arc(24, 24, 24, 0, Math.PI * 2 * process / 100, false);
        context.closePath();
        context.fillStyle = 'rgb(234,117,96)';  //圈的百分比
        context.fill();
        context.beginPath();
        context.moveTo(24, 24);
        context.arc(24, 24, 21, 0, Math.PI * 2, true);
        context.closePath();
        context.fillStyle = 'rgba(255,255,255,1)';
        context.fill();
        context.beginPath();
        context.arc(24, 24, 18.5, 0, Math.PI * 2, true);
        context.closePath();
        context.strokeStyle = '#ddd';
        context.stroke();
        context.font = "bold 9pt Arial";
        context.fillStyle = 'rgb(234,117,96)';  //百分比数字颜色
        context.textAlign = 'center';
        context.textBaseline = 'middle';
        context.moveTo(24, 24);
        context.fillText(text, 24, 24);
    }
    
    $("#IDCardFront").change(function () {
    
        if ($("#FrontUpload").length > 0) {
    
        } else {
            $("#li_idCard").wrap("<form id='FrontUpload' action='upload.php' method='post' enctype='multipart/form-data'></form>");
        }
    
        $("#FrontUpload").ajaxSubmit({
            
            dataType: 'json',
            beforeSend: function () {
            
            },
            uploadProgress: function (event, position, total, percentComplete) {
                $('#percent1').hide();
                $('#process1').show();
                $('#process1').text(percentComplete + "%");
                drawProcess('process1');
            },
            success: function (data) {
                if (data.result == 'true') {
                    $('#img').attr('src','./'+data.img+'');
                } else {
                    alert('上传失败');
                }
            }
        });
    });
    </script>
    

    服务器端用的是PHP

    upload.php代码:

    <?php
    
    error_reporting(0);//禁用错误报告
    
    if (file_exists("./" . $_FILES["IDCardFront"]["name"])){
            $arrRet=array(
                'result'=>'false'
            );
    }else{
            $ret=move_uploaded_file($_FILES["IDCardFront"]["tmp_name"],"./" . $_FILES["IDCardFront"]["name"]);
            if($ret){
                  $arrRet=array(
                    'result'=>'true',
                    'img'=> $_FILES["IDCardFront"]["name"]
                    );
            }else{
                $arrRet=array(
                    'result'=>'false'
                );
            }
    }
    
    echo json_encode($arrRet);
    
    ?>
    

    实现效果:

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          本文标题:js实现图片上传预览及进度圆圈

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