Hello Yurii
  
 Seems we agree on steps 1 - 4  
 but step five is not working on my but
  
 have tried a few options and have not figured how to get this working but will keep focusing on it
  
 unless you can easily see what am missing
  
 here the last part of my javascript that allows users to draw a signature  
 all works well other then sending sig to database
  
 ***************************************************************************************** 
     
Bezier.prototype._point = function (t, start, c1, c2, end) { 
         return          start * (1.0 - t) * (1.0 - t)  * (1.0 - t) 
                + 3.0 *  c1    * (1.0 - t) * (1.0 - t)  * t 
                + 3.0 *  c2    * (1.0 - t) * t          * t 
                +        end   * t         * t          * t; 
     };
 
 })(document);
 
 var canvas = jQuery("signature_pad");
  
 var c = canvas[0];
 
 var ctx = c.getContext("2d");
 
 //Get base64String.
 
 var base64String = c.toDataURL();
 
 console.log("base64String = " + base64String);
 
 //Store base64 to LSV.
 
 localStorage.setItem("signBase64", base64String);
 
 //Where "datasourceName" is datasource from 1st step.
 
 Signature.invoke();
  
 console.log('https://api.appery.io/rest/1/db/colle...');
 
 ****************************************************************************************************** 
 
Thanks much