Html5 canvas簽名插件---jq-signature

常用的canvas簽名插件

http://www.htmleaf.com/html5/html5-canvas/201505281921.html

引入：

<script src="jquery/1.11.0/jquery.min.js"></script>
<script src="jq-signature.js"></script> 

結構：

<div class="js-signature"
     data-width="600"
     data-height="200"
     data-border="1px solid #1ABC9C"
     data-background="#16A085"
     data-line-color="#fff"
     data-auto-fit="true">
</div>  

<button id="clearBtn" onclick="clearCanvas();">Clear Canvas</button>
<button id="saveBtn" onclick="saveSignature();" disabled>Save Signature</button> 

<div id="signature"></div>

初始化：

$(document).on('ready', function() {
  $('.js-signature').jqSignature();
});
 
function clearCanvas() {
  $('#signature').html('<p><em>Your signature will appear here when you click "Save Signature"</em></p>');
  $('.js-signature').jqSignature('clearCanvas');
  $('#saveBtn').attr('disabled', true);
}
 
function saveSignature() {
  $('#signature').empty();
  var dataUrl = $('.js-signature').jqSignature('getDataURL');
  var img = $('<img>').attr('src', dataUrl);
  $('#signature').append($('<p>').text("Here's your signature:"));
  $('#signature').append(img);
}
 
$('.js-signature').on('jq.signature.changed', function() {
  $('#saveBtn').attr('disabled', false);
});