js上传实现进度圆圈以及图片预览

过去项目的需求：
1、上传身份证照片时显示上传时的进度效果；
2、上传结束后预览照片；

先附上图：

完整案例下载地址：http://download.csdn.net/download/webtoy/9970435

思路：
1、引入jquery.form.js插件；
2、ajaxSubmit上传以及canvas画圈，在ajaxSubmit的uploadProgress方法中 传参关联上传进度，上传成功后设置照片路径。

html代码如下：

    <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>

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;
        }

js

    //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);
}


// 上传事件
$("#IDCardFront").change(function () {

    if ($("#FrontUpload").length>0) {
    } else {
        $("#li_idCard").wrap("
");
    }

    $("#FrontUpload").ajaxSubmit({

        dataType: 'json',
        beforeSend: function () {

        },
        //参数不可减少
        uploadProgress: function (event, position, total, percentComplete) {
            $('#percent1').hide();
            $('#process1').show();
            $('#process1').text(percentComplete + "%"); //上传进度
            drawProcess('process1');
        },
        success: function (data) {
            if (data.result == 'true') {
                $('#img').attr('src','./'+data.img+'');
            } else {
                alert('上传失败');
            }
        }
    });
});

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);

?>

本篇完。