array.js

  var signaturePads = [];
         var studentSignaturePad = new SignaturePad(document.getElementById('student-signature-pad'), {
           backgroundColor: 'rgba(255, 255, 255, 0)',
           penColor: 'rgb(0, 0, 0)'
         });
         var saveButton = document.getElementById('submit');
         var cancelButton = document.getElementById('clear1');

         var trainerSignaturePad = new SignaturePad(document.getElementById('trainer-signature-pad'), {
           backgroundColor: 'rgba(255, 255, 255, 0)',
           penColor: 'rgb(0, 0, 0)'
         });
         var saveButton = document.getElementById('submit-button');
         var cancelButton = document.getElementById('clear2');

         cancelButton.addEventListener('click', function (event) {
           trainerSignaturePad.clear();
         });

         var employerSignaturePad = new SignaturePad(document.getElementById('employer-signature-pad'), {
           backgroundColor: 'rgba(255, 255, 255, 0)',
           penColor: 'rgb(0, 0, 0)'
         });
         var saveButton = document.getElementById('submit-button');
         var cancelButton = document.getElementById('clear3');

         cancelButton.addEventListener('click', function (event) {
           employerSignaturePad.clear();
         });

         signaturePads.push(studentSignaturePad);
         signaturePads.push(trainerSignaturePad);
         signaturePads.push(employerSignaturePad);


 function checksig(){
		 for(var i in signaturePads) {
		   if (signaturePads[i].isEmpty){
			   $.each(signaturePads , function(index, val){
				   alert(signaturePads[i])
			   });
		   }
		 }
	   };