我制作了一个我想要的计算器，value="$sm8totalD"依赖于此if语句，
if ($sm8jobs <= "20" ) { echo "0"; } else {echo $sm8total;}
我可以让if语句在表单中运行，但我不确定如何在表单中连接它？如有任何帮助，我们将不胜感激，代码如下。链接：http://www.vestedutility.com.au/ec/inc/calculator.php#
<?php
if (isset($_POST['sm8charge'])) $sm8charge= $_POST['sm8charge'];
if (isset($_POST['sm8jobs'])) $sm8jobs = $_POST['sm8jobs'];
if (isset($_POST['vrrate'])) $vrrate = $_POST['vrrate'];
if (isset($_POST['vrhours'])) $vrhours = $_POST['vrhours'];
if (isset($_POST['vurate'])) $vurate= $_POST['vurate'];
if (isset($_POST['vujobs'])) $vujobs= $_POST['vujobs'];
if (isset($_POST['bkrate'])) $bkrate= $_POST['bkrate'];
if (isset($_POST['bkhours'])) $bkhours= $_POST['bkhours'];
$sm8total = $sm8charge * ($sm8jobs - 20);
$vrtotal = $vrrate * $vrhours;
$vutotal = $vurate * ($vujobs - 2);
$bktotal= $bkrate * $bkhours;
$tmc= $sm8total + $vrtotal + $vutotal + $bktotal;
$sm8totalD="$ ".number_format($sm8total, 2);
$vrtotalD="$ ".number_format($vrtotal, 2);
$vutotalD="$ ".number_format($vutotal, 2);
$bktotalD="$ ".number_format($bktotal, 2);
$tmcD="$ ".number_format($tmc, 2);
if ($sm8jobs <= "20" ) { echo "0"; } else {echo $sm8total;}
echo <<<_END
<body oninput="Javascript: document.vu.submit();">
<form id="ve" name="vu" method='post' action='#'>
<table border='0' width='500px' cellpadding='3' cellspacing='1' class="table">
<tr class="calcheading">
<td class="priceHeading" colspan="4"><strong>Pricing Calculator</strong></td>
</tr>
<tr class="calcrow">
<td class="heading"><a class="buttonheading" href="http://www.vestedutility.com.au/ec/servicem8.php" class="heading"><div class="bheading">Job Management ServiceM8</div></a></td>
<td class="price" align="center">
<b>Price per job:</b>
<input class="fixed" type='text' name='sm8charge' value="0.50"/>
50c
</td>
<td class="infoTask">
<b>Number of jobs processed. The first 20 jobs are free.</b>
</td>
<td class="invalue" align="center">
<input class="input" type='text' name='sm8jobs' value="$sm8jobs" placeholder="50"/>
</td>
<td align="center">
<input class="total" type="text" value="$sm8totalD">
if ($sm8jobs <= "20" ) { echo "0"; } else {echo $sm8total;}
</td>
<td class="signup"><a class="buttonsignup" href="http://www.vestedutility.com.au/ec/index.php" class="heading"><div class="bsignup">Sign me up</div></a></td>
<tr class="calcrow">
<td class="heading">
<a class="buttonheading" href="http://www.vestedutility.com.au/ec/reception.php" class="heading"><div class="bheading">Virtual Reception</div></a></td>
<td class="price" align="center">
<b>Hourly Rate:</b>
<input class="fixedpr" type='text' name='vrrate' value="49.50"/>$49.50
</td>
<td class="infoTask">
Number of hours, incoming calls are calculated in 5 minute increments.
</td>
<td class="invalue" align="center">
<input class="input" type='text' name='vrhours' value="$vrhours" placeholder="10"/>
</td>
<td align="center">
<input class="total" type="text" value="$vrtotalD"></td>
<td class="signup"><a class="buttonsignup" href="http://www.vestedutility.com.au/ec/index.php" class="heading"><div class="bsignup">Sign me up</div></a></td>
<tr class="calcrow">
<td class="heading">
<a class="buttonheading" href="http://www.vestedutility.com.au/ec/marketing.php" class="heading"><div class="bheading">Vested Utility Job Leads</div></a></td>
<td class="price" align="center">
<b>Price per job lead:</b>
<input class="fixedpr" type='text' name='vurate' value="20.00"/>$20.00
</td>
<td class="infoTask">
Number of job leads. The first 2 jobs per month are free.
</td>
<td class="invalue" align="center">
<input class="input" type='text' name='vujobs' value="$vujobs" placeholder="4"/>
</td>
<td class="price" align="center">
<input class="total" type="text" value="$vutotalD"></td>
<td class="signup"><a class="buttonsignup" href="http://www.vestedutility.com.au/ec/index.php" class="heading"><div class="bsignup">Sign me up</div></a></td>
<tr class="calcrow">
<td class="heading">
<a class="buttonheading" href="http://www.vestedutility.com.au/ec/bookkeeping.php" class="heading"><div class="bheading">Accounts - Bookkeeping</div></a></td>
<td class="price" align="center">
<b>Hourly Rate:</b>
<input class="fixedpr" type='text' name='bkrate' value="49.50"/>$49.50
</td>
<td class="infoTask">
Number of hours.
</td>
<td class="invalue" align="center">
<input class="input" type='text' name='bkhours' value="$bkhours" placeholder="5"/>
</td>
<td align="center">
<input class="total" type="text" value="$bktotalD"></td>
<td class="signup"><a class="buttonsignup" href="http://www.vestedutility.com.au/ec/index.php" class="heading"><div class="bsignup">Sign me up</div></a></td>
<tr class="calcrow tmc">
</tr>
<tr class="calcrow tmc">
<td class="extra" colspan="2]"></td>
<td class="tmc" colspan="2">
<strong class="header">Total Monthly Cost</strong>
All prices are calcualted on a monthly basis and GST is not charged.
</td>
<td class="tmcD " align="center"><input class="total" type="text" value="$tmcD"></td>
<tr class="submit">
<td colspan="2">
<input type='submit' value='Calculate'/>
</td>
</tr>
_END;
?>
</table>
</form>
</body>
您似乎使用了heredoc，而像if这样的语句在heredoc中是不可能的，所以您需要在@echo@之前为if语句的结果定义新的变量，并将其打印在右侧中
...
if ($sm8jobs <= "20" ) { $output = 0; } else {$output = $sm8total;}
echo <<<_END
...
$output
...
_END;