PHP $ _GET和未定义的索引 [英] php $_GET and undefined index
问题描述
当我尝试在其他PHP服务器上运行脚本时，出现了一个新问题.
A new problem has arisen for me as I tried to run my script on a different PHP Server.
在旧服务器上，即使未声明s参数，以下代码也可以正常工作.
ON my old server the following code appears to work fine - even when no s parameter is declared.
<?php
if ($_GET['s'] == 'jwshxnsyllabus')
echo "<body onload=\"loadSyllabi('syllabus', '../syllabi/jwshxnporsyllabus.xml', '../bibliographies/jwshxnbibliography_')\">";
if ($_GET['s'] == 'aquinas')
echo "<body onload=\"loadSyllabi('syllabus', '../syllabi/AquinasSyllabus.xml')\">";
if ($_GET['s'] == 'POP2')
echo "<body onload=\"loadSyllabi('POP2')\">";
elseif ($_GET['s'] == null)
echo "<body>"
?>
但是现在，在未定义s的值的情况下，在本地计算机(XAMPP-Apache)上的本地服务器上，出现以下错误.
But now, on a my local server on my local machine (XAMPP - Apache) I get the following error when no value for s is defined.
Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 43
Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 45
Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 47
Notice: Undefined index: s in C:\xampp\htdocs\teaching\index.php on line 49
如果为s声明了值，但脚本要调用某些javascript函数会发生什么，但是如果未声明任何内容，我希望页面能够正常加载.
What I want to happen for the script to call certain javascript functions if a value is declared for s, but if nothing is declared i would like the page to load normally.
你能帮我吗?
推荐答案
错误报告不会在以前的服务器上包含通知，这就是为什么您没有看到错误的原因.
Error reporting will have not included notices on the previous server which is why you haven't seen the errors.
在尝试使用索引s之前，应该检查索引s是否确实存在于数组$_GET中.
You should be checking whether the index s actually exists in the $_GET array before attempting to use it.
像这样的东西就足够了:
Something like this would be suffice:
if (isset($_GET['s'])) {
if ($_GET['s'] == 'jwshxnsyllabus')
echo "<body onload=\"loadSyllabi('syllabus', '../syllabi/jwshxnporsyllabus.xml', '../bibliographies/jwshxnbibliography_')\">";
else if ($_GET['s'] == 'aquinas')
echo "<body onload=\"loadSyllabi('syllabus', '../syllabi/AquinasSyllabus.xml')\">";
else if ($_GET['s'] == 'POP2')
echo "<body onload=\"loadSyllabi('POP2')\">";
} else {
echo "<body>";
}
使用switch语句来提高代码的可读性(如果打算增加更多的案例)可能是有益的.
It may be beneficial (if you plan on adding more cases) to use a switch statement to make your code more readable.
switch ((isset($_GET['s']) ? $_GET['s'] : '')) {
case 'jwshxnsyllabus':
echo "<body onload=\"loadSyllabi('syllabus', '../syllabi/jwshxnporsyllabus.xml', '../bibliographies/jwshxnbibliography_')\">";
break;
case 'aquinas':
echo "<body onload=\"loadSyllabi('syllabus', '../syllabi/AquinasSyllabus.xml')\">";
break;
case 'POP2':
echo "<body onload=\"loadSyllabi('POP2')\">";
break;
default:
echo "<body>";
break;
}
顺便说一句，我编写的第一组代码模仿了您的全部意图. ?s=中的意外值的预期结果是要不输出<body>标记，还是疏忽大意?请注意，该开关将始终默认设置为<body>来解决此问题.
BTW, the first set of code I wrote mimics what yours is meant to do in it's entirety. Is the expected outcome of an unexpected value in ?s= meant to output no <body> tag or was this an oversight? Note that the switch will fix this by always defaulting to <body>.
这篇关于PHP $ _GET和未定义的索引的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
