换行
"\r\n"

滚动条自动滚动到结尾
document.form1.text_information.doScroll('down');

滚动条顶部坐标
document.form1.text_information.scrollTop;

textarea自动滚动到结尾
function add_information(info)//添加信息
{
 document.form1.text_information.value=document.form1.text_information.value+info+"\r\n";
 text_info_br++;
 if (text_info_br>document.form1.text_information.rows)
 {
  document.form1.text_information.scrollTop=(text_info_br-document.form1.text_information.rows)*20;
 }
}