代码检测textarea内填写的长度，未填写时提示需要重新填写，少于15字符时提示需要长于15字符，成功时显示所填写建议。
代码
function confirm()
{
if($("#advice").val().length == 0)
{
alert("We can't see your advice. Maybe you should fill the form first.");
$("#advice").focus();
return false;
}
else if($("#advice").val().length <= 15)
{
alert("Your advice should longer than 15 letters.");
$("#advice").focus();
return false;
}
else
{
alert("Thank you for your advice! You will get out reply in 24 hours for advice:\n"+$("#advice").val());
return true;
}
}