html5 - php中添加了如下語句出現空白頁 刪除頁面zhengchang

添加如下幾天語句頁面變為空白，刪除正常
echo "isset($tireqty)".isset($tireqty)."
";
echo "isset($nothere)".isset($nothere)."
";
echo "isset($tireqty)".empty($tireqty)."
";
echo "isset($nothere)".empty($nothere)."
";

下面列出完整代碼

                Bob's Auto Parts -Order Result                    
Bos's Auto Parts
            
Order Result
            Order processed at".date('H:i, jS F Y')."
";                    echo " 
Your order is as follow:
";                    echo $tireqty." tireqty
";                    echo $oilqty." oilqty
";                    echo $sparkqty." spark plugs 
";                    $totalqty = 0;                    $totalqty = $tireqty + $oilqty + $sparkqty;                    echo "Items ordered: ".$totalqty."
";                    $totalamount = 0.00;                    $totalamount = $tireqty * TIREPRICE +                     $oilqty * OILPRICE + $sparkqty * SPARKPRICE;                    echo "Subtotal: $".number_format($totalamount,2)."
";                    $taxrate = 0.10;        //total sales tax is 10%                    $totalamount = $totalamount * (1 + $taxrate);                    echo "Total including tax: $".number_format($totalamount,2)."
"

// echo "isset($tireqty)".isset($tireqty)."
";
// echo "isset($nothere)".isset($nothere)."
";
// echo "isset($tireqty)".empty($tireqty)."
";
// echo "isset($nothere)".empty($nothere)."
";

            ?>    

回複內容：

添加如下幾天語句頁面變為空白，刪除正常
echo "isset($tireqty)".isset($tireqty)."
";
echo "isset($nothere)".isset($nothere)."
";
echo "isset($tireqty)".empty($tireqty)."
";
echo "isset($nothere)".empty($nothere)."
";

下面列出完整代碼

                Bob's Auto Parts -Order Result                    
Bos's Auto Parts
            
Order Result
            Order processed at".date('H:i, jS F Y')."
";                    echo " 
Your order is as follow:
";                    echo $tireqty." tireqty
";                    echo $oilqty." oilqty
";                    echo $sparkqty." spark plugs 
";                    $totalqty = 0;                    $totalqty = $tireqty + $oilqty + $sparkqty;                    echo "Items ordered: ".$totalqty."
";                    $totalamount = 0.00;                    $totalamount = $tireqty * TIREPRICE +                     $oilqty * OILPRICE + $sparkqty * SPARKPRICE;                    echo "Subtotal: $".number_format($totalamount,2)."
";                    $taxrate = 0.10;        //total sales tax is 10%                    $totalamount = $totalamount * (1 + $taxrate);                    echo "Total including tax: $".number_format($totalamount,2)."
"

// echo "isset($tireqty)".isset($tireqty)."
";
// echo "isset($nothere)".isset($nothere)."
";
// echo "isset($tireqty)".empty($tireqty)."
";
// echo "isset($nothere)".empty($nothere)."
";

            ?>    

前面的引號類的變數$nothere沒有定義會報錯，你沒有開啟debug模式就不會報錯，也不會顯示
isset和empty返回的都是bool類型，自然是不會顯示的

echo "isset($tireqty)"...如果$tireqty沒有定義會出錯，因為這裡雙引號裡面的isset是作為字元輸出的

error_reporting(E_ALL);
ini_set("display_errors", 1);

添加到頁面頂端

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