// 根據指定正表示式，來控制OBJ表示
                function mask(objTextBox,mask)
                {
                        // 掩碼
                        expMask = new RegExp(mask);

                        // 當前文字框中的文字
                        var strText =objTextBox.value;
                        // 文字長度
                        var nTextLen=strText.length;

                        // 當前游標位置
                        var nCursorPos=getPos(objTextBox);

                        // 按下的鍵碼
                        var nKeyCode = window.event.keyCode;
                        if (nKeyCode > 95) nKeyCode -= (95-47);

                        // 封住傳統處理
                        window.event.returnValue = false;
                        // 自行處理按鈕
                        switch (nKeyCode)
                        {
                                case 8:// 如果動作是退格[<-]
                                {
                                        strText =  strText.substr(0,nCursorPos-1) + strText.substr(nCursorPos, nTextLen-nCursorPos);
                                        nCursorPos--;
                                        break;
                                }
                                case 46:// 如果動作是del[del]
                                {
                                        strText =  strText.substr(0,nCursorPos) + strText.substr(nCursorPos+1,nTextLen-nCursorPos-1);
                                        nCursorPos--;
                                        break;
                                }
                                case 38:// 如果動作是方向鍵[上]
                                case 39:// 如果動作是方向鍵[右]
                                {
                                        nCursorPos++;
                                        break;
                                }
                                case 37:// 如果動作是方向鍵[左]
                                case 40:// 如果動作是方向鍵[下]
                                {
                                        nCursorPos--;
                                        break;
                                }
                                default :
                                {
                                        strText =  strText.substr(0,nCursorPos) + String.fromCharCode(nKeyCode) + strText.substr(nCursorPos,nTextLen);

                                        nCursorPos++;
                                        if (nCursorPos>strText.length)
                                        {
                                                nCursorPos=strText.length;
                                        }
                                        break;
                                }

                        }

                        if (strText.match(expMask))
                        {
                                // 輸入格式正確
                                objTextBox.value = strText;
                        }

                        // 移動游標
                        setCursor(objTextBox,nCursorPos);
                }

                // 得到一個文字框控制元件的當前游標位置
                function getPos(obj)
                {
                        obj.focus();
                        var workRange=document.selection.createRange();
                        obj.select();
                        var allRange=document.selection.createRange();
                        workRange.setEndPoint("StartToStart",allRange);
                        var len=workRange.text.length;
                        workRange.collapse(false);
                        workRange.select();

                        return len;
                }

                // 設定一個文字框控制元件的當前游標位置
                function setCursor(obj,num){
                        range=obj.createTextRange();
                        range.collapse(true);
                        range.moveStart('character',num);

                        range.select();
                }