JS获取跟设置光标的位置 _JavaScript

JS获取和设置光标的位置

<html>
<head>
<script language="javascript">
function getCursortPosition (ctrl) {//获取光标位置函数
	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;
	return (CaretPos);
}

function setCaretPosition(ctrl, pos){//设置光标位置函数
	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();
	}
}

function A(){
alert(getCursortPosition(document.getElementById("a")));	
}
function B()
{
    setCaretPosition(document.getElementById("a"),5);
}
</script>
</head>

<body>
<input id="a" type=text name=text1 value="" >
<button onclick="A();">获取</bottun>
    <button onclick="B();">设置</bottun>
</body>
</html>

onkeyup ="LowerToUpper(this,event.keyCode);"

//小写转大写
function LowerToUpper(element,keyCode)
{
    if ((keyCode > 40 || keyCode < 35) && keyCode != 8) {
        var pos = getCursortPosition(element);
        element.value = element.value.toUpperCase();
        setCaretPosition(element, pos);
    }
}