html5手写签名的实现示例

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    <script src="/js/modernizr.js"></script>
    <!--[if lt IE 9]>
    <script type="text/javascript" src="libs/flashcanvas.js"></script>
    <![endif]-->
    <style type="text/css">
        div {
            margin-top:1em;
            margin-bottom:1em;
        }
        input {
            padding: .5em;
            margin: .5em;
        }
        select {
            padding: .5em;
            margin: .5em;
        }
        #signatureparent {
            color:darkblue;
            background-color:darkgrey;
            /*max-width:600px;*/
            padding:20px;
        }
        /*This is the div within which the signature canvas is fitted*/
        #signature {
            border: 2px dotted black;
            background-color:lightgrey;
        }
        /* Drawing the 'gripper' for touch-enabled devices */
        html.touch #content {
            float:left;
            width:92%;
        }
        html.touch #scrollgrabber {
            float:right;
            width:4%;
            margin-right:2%;
            background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAFCAAAAACh79lDAAAAAXNSR0IArs4c6QAAABJJREFUCB1jmMmQxjCT4T/DfwAPLgOXlrt3IwAAAABJRU5ErkJggg==)
        }
        html.borderradius #scrollgrabber {
            border-radius: 1em;
        }
    </style>
</head>
<body>
<div>
    <div id="content">
        <div id="signatureparent">
            <div>jSignature inherits colors from parent element. Text = Pen color. Background = Background. (This works even when Flash-based Canvas emulation is used.)</div>
            <div id="signature"></div></div>
        <div id="tools"></div>
        <div><p>Display Area:</p><div id="displayarea"></div></div>
    </div>
    <div id="scrollgrabber"></div>
</div>
<script src="/js/jquery-3.2.1.min.js"></script>
<script type="text/javascript">
    jQuery.noConflict()
</script>
<script>
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</script>
<script src="/js/jSignature.min.noconflict.js"></script>
<script>
    (function($){
        $(document).ready(function() {
            // This is the part where jSignature is initialized.
            var $sigdiv = $("#signature").jSignature({'UndoButton':true})
                // All the code below is just code driving the demo.
                , $tools = $('#tools')
                , $extraarea = $('#displayarea')
                , pubsubprefix = 'jSignature.demo.'
            var export_plugins = $sigdiv.jSignature('listPlugins','export')
                , chops = ['<span><b>提取签名数据: </b></span><select>','<option value="">(select export format)</option>']
                , name
            for(var i in export_plugins){
                if (export_plugins.hasOwnProperty(i)){
                    name = export_plugins[i]
                    chops.push('<option value="' + name + '">' + name + '</option>')
                }
            }
            chops.push('</select><span><b> or: </b></span>')
            $(chops.join('')).bind('change', function(e){
                if (e.target.value !== ''){
                    var data = $sigdiv.jSignature('getData', e.target.value)
                    $.publish(pubsubprefix + 'formatchanged')
                    if (typeof data === 'string'){
                        $('textarea', $tools).val(data)
                    } else if($.isArray(data) && data.length === 2){
                        $('textarea', $tools).val(data.join(','))
                        $.publish(pubsubprefix + data[0], data);
                    } else {
                        try {
                            $('textarea', $tools).val(JSON.stringify(data))
                        } catch (ex) {
                            $('textarea', $tools).val('Not sure how to stringify this, likely binary, format.')
                        }
                    }
                }
            }).appendTo($tools)
            $('<input type="button" value="Reset">').bind('click', function(e){
                $sigdiv.jSignature('reset')
            }).appendTo($tools)
            $('<div><textarea style="width:100%;height:7em;"></textarea></div>').appendTo($tools)
            $.subscribe(pubsubprefix + 'formatchanged', function(){
                $extraarea.html('')
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            $.subscribe(pubsubprefix + 'image/svg+xml', function(data) {
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                    var i = new Image()
                    i.src = 'data:' + data[0] + ';base64,' + btoa( data[1] )
                    $(i).appendTo($extraarea)
                } catch (ex) {
                }
                var message = [
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                    , "Try this page in a modern browser to see the SVG on the page, or export data as plain SVG, save to disk as text file and view in any SVG-capabale viewer."
                ]
                $( "<div>" + message.join("<br/>") + "</div>" ).appendTo( $extraarea )
            });
            $.subscribe(pubsubprefix + 'image/svg+xml;base64', function(data) {
                var i = new Image()
                i.src = 'data:' + data[0] + ',' + data[1]
                $(i).appendTo($extraarea)
                var message = [
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                ]
                $( "<div>" + message.join("<br/>") + "</div>" ).appendTo( $extraarea )
            });
            $.subscribe(pubsubprefix + 'image/png;base64', function(data) {
                var i = new Image()
                i.src = 'data:' + data[0] + ',' + data[1]
                $('<span><b>As you can see, one of the problems of "image" extraction (besides not working on some old Androids, elsewhere) is that it extracts A LOT OF DATA and includes all the decoration that is not part of the signature.</b></span>').appendTo($extraarea)
                $(i).appendTo($extraarea)
            });
            $.subscribe(pubsubprefix + 'image/jsignature;base30', function(data) {
                $('<span><b>This is a vector format not natively render-able by browsers. Format is a compressed "movement coordinates arrays" structure tuned for use server-side. The bonus of this format is its tiny storage footprint and ease of deriving rendering instructions in programmatic, iterative manner.</b></span>').appendTo($extraarea)
            });
            if (Modernizr.touch){
                $('#scrollgrabber').height($('#content').height())
            }
        })
    })(jQuery)
</script>
</body>
</html>

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