Added option to allow retention of partially filled in masked fields

Cakefile

@@ -1,4 +1,4 @@
-sys = require 'sys'
+util = require 'util'
 fs = require 'fs'
 path = require 'path'
 uglify = require 'uglify-js'
@@ -29,7 +29,7 @@ replaceTokens = (js,tokens)->
 
 task 'compress', 'compress javascript', ->
 	invoke 'clean'
-	fs.mkdir(distPath,0755)
+	fs.mkdir(distPath,0o0755)
 	compressed = minify(fs.readFileSync('src/jquery.maskedinput.js','utf8'))
 	final=replaceTokens(compressed,plugin)
 	fs.writeFileSync(path.join(distPath,'jquery.maskedinput.min.js'), final)

spec/Focus.Spec.js

@@ -62,6 +62,32 @@ feature("Leaving A Masked Input",function(){
 	});
 });
 
+feature("Leaving A Masked Input With retainPartial",function(){
+	scenario("All placeholders filled",function(){
+		given("a mask with two placeholders",function(){
+			input.mask("99", { retainPartial: true });
+		});
+		when("typing two characters and blurring",function(){
+			input.mashKeys("12").blur();
+		});
+		then("value should be correct",function(){
+			expect(input).toHaveValue("12");
+		});
+	});
+
+	scenario("Empty placeholders remaining",function(){
+		given("a mask with two placeholders",function(){
+			input.mask("99");
+		});
+		when("typing one character and blurring",function(){
+			input.mashKeys("1").blur();
+		});
+		then("value should be empty",function(){
+			expect(input).toHaveValue("");
+		});
+	});
+});
+
 feature("Optional marker",function(){
 	scenario("Placeholders not filled to marker",function(){
 		given("a mask with an optional marker",function(){

src/jquery.maskedinput.js

@@ -206,8 +206,10 @@
 						}
 					}
 					if (!allow && lastMatch + 1 < partialPosition) {
-						input.val("");
-						clearBuffer(0, len);
+						if (lastMatch == 0 || ! settings.retainPartial) {
+							input.val("");
+							clearBuffer(0, len);
+						}
 					} else if (allow || lastMatch + 1 >= partialPosition) {
 						writeBuffer();
 						if (!allow) input.val(input.val().substring(0, lastMatch + 1));