Mask: Initial draft of _caret, implementation borrowed from @digitalBush

 maskedInput plugin

tests/unit/mask/mask.html

@@ -32,7 +32,7 @@ <h2 id="qunit-banner"></h2>
 <h2 id="qunit-userAgent"></h2>
 <ol id="qunit-tests"></ol>
 <div id="qunit-fixture">
-
+<input id="mask1" type="text">
 </div>
 </body>
 </html>

tests/unit/mask/mask_core.js

@@ -2,4 +2,30 @@
 
 module( "mask: core" );
 
+test( "_caret() can move and read the text cursor", function() {
+	expect( 3 );
+
+	var input = $( "#mask1" ).val("This string is 33 characters long").mask(),
+		instance = input.data( "mask" );
+	input.focus();
+
+	instance._caret( 0 );
+	deepEqual( instance._caret(), {
+		begin: 0,
+		end: 0
+	}, "Caret position set to 0 results in 0, 0" );
+
+	instance._caret( 34 );
+	deepEqual( instance._caret(), {
+		begin: 33,
+		end: 33
+	}, "Caret position set beyond bounds (34) results in 33, 33" );
+
+	instance._caret( 0, 2 );
+	deepEqual( instance._caret(), {
+		begin: 0,
+		end: 2
+	}, "Caret position set to 0, 2 results in 0, 2" );
+});
+
 }( jQuery ) );

ui/jquery.ui.mask.js

@@ -18,8 +18,45 @@ $.widget( "ui.mask", {
 	},
 	_create: function() {
 
+	},
+
+	// helper function to get or set position of text cursor (caret)
+	_caret: function( begin, end ) {
+		var range,
+			elem = this.element,
+			dom = elem[0];
+
+		// if begin is defined, we are setting a range
+		if ( begin !== undefined ) {
+			end = ( end === undefined ) ? begin : end;
+			if ( dom.setSelectionRange ) {
+				dom.setSelectionRange( begin, end );
+			} else if ( dom.createTextRange ) {
+				range = dom.createTextRange();
+				range.collapse( true );
+				range.moveEnd( "character", end );
+				range.moveStart( "character", begin );
+				range.select();
+			}
+		} else {
+
+			// begin is undefined, we are reading the range
+			if ( dom.setSelectionRange ) {
+				begin = dom.selectionStart;
+				end = dom.selectionEnd;
+			} else if ( document.selection && document.selection.createRange ) {
+				range = document.selection.createRange();
+
+				// the moveStart returns the number of characters it moved as a negative number
+				begin = 0 - range.duplicate().moveStart( "character", -100000 );
+				end = begin + range.text.length;
+			}
+			return {
+				begin: begin,
+				end: end
+			};
+		}
 	}
 });
 
-
-})( jQuery );
+}( jQuery ) );