function checkLength() { var fMsgLen = 300 - $("#message").val().length; $("#messageLength").html(fMsgLen); if(fMsgLen < 0) { $("#buttonMesage").attr("disabled", "true"); } else { $("#buttonMesage").removeAttr("disabled"); } } function checkForm() { var fMsgLen = 300 - $("#message").val().length; $("#buttonMesage").attr("disabled", "true"); if($("#message").val() == ' ') { $("#buttonMesage").removeAttr("disabled"); alert('请输入留言内容!'); return false; } else if(fMsgLen < 0) { alert('您的留言内容请控制在 300 个字之内。'); $("#buttonMesage").removeAttr("disabled"); return false; } else { $('#messageForm').submit(); $("#buttonMesage").removeAttr("disabled"); return true; } }