JavaScript gets the cursor position and sets the cursor position

In the project development often encountered input and so set the cursor position to the final question, today I checked Google, found in IE, Firefox, Opera and other mainstream browsers to get the cursor position (getcursortposition) and set the cursor position (setcursorposition) function.

function Getcursortposition (ctrl) {//Get cursor position functions
	var caretpos = 0;	IE Support
	if (document.selection) {
	ctrl.focus ();
		var Sel = Document.selection.createRange ();
		Sel.movestart (' character ',-ctrl.value.length);
		Caretpos = Sel.text.length;
	}
	Firefox Support
	else if (Ctrl.selectionstart | | ctrl.selectionstart = = ' 0 ')
		caretpos = ctrl.selectionstart;< C11/>return (Caretpos);
}

PS: Parameter ctrl is input or TextArea object

function Setcaretposition (CTRL, POS) {//SET cursor position functions
	if (ctrl.setselectionrange)
	{
		ctrl.focus ();
		Ctrl.setselectionrange (Pos,pos);
	}
	else if (ctrl.createtextrange) {
		var range = Ctrl.createtextrange ();
		Range.collapse (true);
		Range.moveend (' character ', POS);
		Range.movestart (' character ', POS);
		Range.Select ();
	}
PS: Parameter ctrl is input or TextArea object, POS is the location where the cursor is to be moved.