function insertAtCaret(areaElement,textFeildValue){
var textObj = areaElement;
// 兼容不支持 selectionStart 浏览器
if(document.all && textObj.createTextRange && textObj.caretPos){
var caretPos=textObj.caretPos;
caretPos.text = caretPos.text.charAt(caretPos.text.length-1) == '' ?
textFeildValue+'' : textFeildValue;
}
else if(textObj.setSelectionRange){
var rangeStart=textObj.selectionStart;
var rangeEnd=textObj.selectionEnd;
var tempStr1=textObj.value.substring(0,rangeStart);
var tempStr2=textObj.value.substring(rangeEnd);
textObj.value=tempStr1+textFeildValue+tempStr2;
textObj.focus();
var len=textFeildValue.length;
textObj.setSelectionRange(rangeStart+len,rangeStart+len); // 移动光标到添加内容之后
}
else {
textObj.value+=textFeildValue;
}
return true;
}