为什么这个PHP代码行在我的虚拟主机上导致语法错误，而不是在c9上？

Question

这是一行代码，如果没有SESSION，文本区域应为空白。如果有SESSION，请将内容放入textarea。这里真的有错误，还是仅仅是虚拟主机的问题？

<form id="translateform" action="processTranslation.php" method="post"><?php 
echo "<textarea maxlength='3000' id='inputField' placeholder='Enter your Lorem Ipsum text here:' name='translate'>";
if(isset($_SESSION['text'])){
    echo $_SESSION['text'];
    }
    echo "</textarea>";
        ?>

错误消息：＆＃34; Uncaught SyntaxError：Unexpected Identifier＆＃34;。这几乎是整个代码：

<form id="translateform" action="process.php" method="post"><?php 
if(!empty($_SESSION['text'])){
    echo "<textarea maxlength='3000' id='inputField' placeholder='Enter your Lorem Ipsum text here:' name='translate'>" . $_SESSION['text'] . "</textarea>";
    }
   else{
echo "<textarea maxlength='3000' id='inputField' placeholder='Enter your Lorem Ipsum text here:' name='translate'></textarea>";
}
        ?>
<input type="submit" name="submit" id="submit" value="Submit!">
</form>
<a href="projects.html"><div id="back"><p id="goback">Back!</p></div></a>
<script>
if(document.referrer=="msolonko.net16.net/projects.html"){
document.cookie="navigatedFromSite=agreed";
}
else if(document.referrer!="msolonko.net16.net/projects.html"&&document.referrer!="msolonko.net16.net/LoremIpsum.php"){
 document.cookie = "navigatedFromSite="no";
}
var x=document.cookie;
if(x.search("navigatedFromSite")!=-1&&x.search("agreed")!=-1){
 document.getElementById("back").style.display="initial";
}
</script>
<?php
echo "<div id='containertranslation'><p id='translation'>";
if(isset($_SESSION['translation'])){echo $_SESSION['translation'];}//if translated
else{echo "Translation: ";}//if not, empty field
echo "</p></div>";//adds div with translation

?>

如您所见，我设置cookie以查看用户导航的页面。如果是来自网站，则应显示后退按钮。这适用于cloud9，但不在此托管中。以下是错误消息： 这是第109行：

echo "<textarea maxlength='3000' id='inputField' placeholder='Enter your Lorem Ipsum text here:' name='translate'></textarea>";

这是第119行： else if(document.referrer!="msolonko.net16.net/projects.html"&&document.referrer!="msolonko.net16.net/LoremIpsum.php"){

Answer 1

使用empty($_SESSION)代替isset($_SESSION)检查$_SESSION变量是否为空。

 // checks if the variable is empty or not
 if (!empty($_SESSION['text'])) {
     // display inside <textarea>
     echo "<textarea>" . $_SESSION['text'] . "</textarea>";
 }