diff --git a/spec/Paste.Spec.js b/spec/Paste.Spec.js
index a9ae291..8491f44 100644
--- a/spec/Paste.Spec.js
+++ b/spec/Paste.Spec.js
@@ -13,4 +13,19 @@ feature("Pasting", function() {
 			expect(completed).toBeTruthy();
 		});
 	});
+	
+	scenario('When pasting a value with optional mask',function(){
+		var completed=false;
+		given("an input that contains a '?' character with a completed callback", function(){
+			input.mask("99?99",{completed:function(){completed=true;}});
+		});
+
+		when("pasting",function(){
+			input.val("99").trigger("paste").trigger("input");
+		});
+		waits(1);
+		then("completed callback should be called",function(){
+			expect(completed).toBeTruthy();
+		});
+	});
 });
\ No newline at end of file
diff --git a/spec/Typing.Spec.js b/spec/Typing.Spec.js
index 8fbf155..f02431e 100644
--- a/spec/Typing.Spec.js
+++ b/spec/Typing.Spec.js
@@ -55,4 +55,26 @@ describe("Typing Specifications", function() {
 			});
 		});		
 	});
+	
+	describe("When the mask contains a '?' character and it was typed only required mask", function(){
+		var completed = false;
+		
+		beforeEach(function(){					
+			runs(function(){
+				input
+				.mask("99?99",{completed:function(){completed=true;}})
+				.focus();						
+			});
+			waits(1);
+			runs(function(){
+				input
+				.mashKeys("12");				
+			});
+			waits(1);			
+		});
+		
+		it("callback function should be called", function(){
+			expect(completed).toBeTruthy();
+		});
+	});
 });
\ No newline at end of file
diff --git a/src/jquery.maskedinput.js b/src/jquery.maskedinput.js
index 749da65..21ad5a3 100644
--- a/src/jquery.maskedinput.js
+++ b/src/jquery.maskedinput.js
@@ -65,7 +65,8 @@ $.fn.extend({
 			tests,
 			partialPosition,
 			firstNonMaskPos,
-			len;
+			len,
+			lenNotOptional;
 
 		if (!mask && this.length > 0) {
 			input = $(this[0]);
@@ -75,11 +76,15 @@ $.fn.extend({
 			placeholder: $.mask.placeholder, // Load default placeholder
 			completed: null
 		}, settings);
-
+		
+		function getMaskLengthNotOptional(mask){
+			return mask.indexOf('?') != -1 ? mask.substring(0, mask.indexOf('?')).length : mask.length;
+		}
 
 		defs = $.mask.definitions;
 		tests = [];
 		partialPosition = len = mask.length;
+		lenNotOptional = getMaskLengthNotOptional(mask);
 		firstNonMaskPos = null;
 
 		$.each(mask.split(""), function(i, c) {
@@ -219,7 +224,7 @@ $.fn.extend({
 								input.caret(next);
 							}
 
-							if (settings.completed && next >= len) {
+							if (settings.completed && next >= lenNotOptional) {
 								settings.completed.call(input);
 							}
 						}
@@ -276,7 +281,7 @@ $.fn.extend({
 					input.val(input.val().substring(0, lastMatch + 1));
 				}
 				return (partialPosition ? i : firstNonMaskPos);
-			}
+			}			
 
 			input.data($.mask.dataName,function(){
 				return $.map(buffer, function(c, i) {
@@ -318,7 +323,7 @@ $.fn.extend({
 					setTimeout(function() { 
 						var pos=checkVal(true);
 						input.caret(pos); 
-						if (settings.completed && pos == input.val().length)
+						if (settings.completed && pos >= lenNotOptional)
 							settings.completed.call(input);
 					}, 0);
 				});