Form post - export base64 text

I would like to export only the base64 (ie: data:image/png;base64, etc) text; not the image. I want to store this is a database field by submitting a form.

So where I need help is what do I put in the form post to accomplish that?

Thanks.

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
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<script src="../libs/modernizr.js"></script>
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<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="../libs/jquery.js"></script>
<script>
/*  @preserve
jQuery pub/sub plugin by Peter Higgins (dante@dojotoolkit.org)
Loosely based on Dojo publish/subscribe API, limited in scope. Rewritten blindly.
Original is (c) Dojo Foundation 2004-2010. Released under either AFL or new BSD, see:
http://dojofoundation.org/license for more information.
*/
(function($) {
	var topics = {};
	$.publish = function(topic, args) {
	    if (topics[topic]) {
	        var currentTopic = topics[topic],
	        args = args || {};
	
	        for (var i = 0, j = currentTopic.length; i < j; i++) {
	            currentTopic[i].call($, args);
	        }
	    }
	};
	$.subscribe = function(topic, callback) {
	    if (!topics[topic]) {
	        topics[topic] = [];
	    }
	    topics[topic].push(callback);
	    return {
	        "topic": topic,
	        "callback": callback
	    };
	};
	$.unsubscribe = function(handle) {
	    var topic = handle.topic;
	    if (topics[topic]) {
	        var currentTopic = topics[topic];
	
	        for (var i = 0, j = currentTopic.length; i < j; i++) {
	            if (currentTopic[i] === handle.callback) {
	                currentTopic.splice(i, 1);
	            }
	        }
	    }
	};
})(jQuery);

</script>
<script src="../src/jSignature.js"></script>
<script src="../src/plugins/jSignature.CompressorBase30.js"></script>
<script src="../src/plugins/jSignature.CompressorSVG.js"></script>
<script src="../src/plugins/jSignature.UndoButton.js"></script> 
<script src="../src/plugins/signhere/jSignature.SignHere.js"></script> 
<script>
$(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>Extract signature data as: </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('')
	})

	$.subscribe(pubsubprefix + 'image/svg+xml', function(data) {

		try{
			var i = new Image()
			i.src = 'data:' + data[0] + ';base64,' + btoa( data[1] )
			$(i).appendTo($extraarea)
		} catch (ex) {

		}
		
		var message = [
			"If you don't see an image immediately above, it means your browser is unable to display in-line (data-url-formatted) SVG."
			, "This is NOT an issue with jSignature, as we can export proper SVG document regardless of browser's ability to display it."
			, "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 = [
			"If you don't see an image immediately above, it means your browser is unable to display in-line (data-url-formatted) SVG."
			, "This is NOT an issue with jSignature, as we can export proper SVG document regardless of browser's ability to display it."
			, "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/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())		
	}
	
})
</script>

</body>
</html>

Edit:

In reviewing my post, I think it might be best to save in the svg format because it takes much less space to store. Therefore, I would like to post that to the database - text part only, not the image.