TextArea光标位置插入文字以及移动光标到文字末尾的JS方法

function insertText(obj,str) {
	obj.focus();
	if (document.selection) {
		var sel = document.selection.createRange();
		sel.text = str;
	} else if (typeof obj.selectionStart == 'number' && typeof obj.selectionEnd == 'number') {
		var startPos = obj.selectionStart,
			endPos = obj.selectionEnd,
			cursorPos = startPos,
			tmpStr = obj.value;
		obj.value = tmpStr.substring(0, startPos) + str + tmpStr.substring(endPos, tmpStr.length);
		cursorPos += str.length;
		obj.selectionStart = obj.selectionEnd = cursorPos;
	} else {
		obj.value += str;
	}
}
function moveEnd(obj){
	obj.focus();
	var len = obj.value.length;
	if (document.selection) {
		var sel = obj.createTextRange();
		sel.moveStart('character',len);
		sel.collapse();
		sel.select();
	} else if (typeof obj.selectionStart == 'number' && typeof obj.selectionEnd == 'number') {
		obj.selectionStart = obj.selectionEnd = len;
	}
}