I';我试图用php$#u GET语句在屏幕上显示一条消息,但它们';我们只是一无所获
为什么不这样做:I';我试图用php$#u GET语句在屏幕上显示一条消息,但它们';我们只是一无所获,php,html,Php,Html,为什么不这样做: <html> <?php $firstName = isset ($_GET["firstName"]); $lastName = isset ($_GET["lastName"]); if(isset($_GET['firstName'])&& isset($_GET['lastName'])){ if (isset($_GET['firstName']) == "Kory" &&
<html>
<?php
$firstName = isset ($_GET["firstName"]);
$lastName = isset ($_GET["lastName"]);
if(isset($_GET['firstName'])&& isset($_GET['lastName'])){
if (isset($_GET['firstName']) == "Kory" && isset($_GET['lastName']) == " ") {
echo "Hello Kory";
}
}
if(isset($_GET['firstName'])&& isset($_GET['lastName'])){
if (isset($_GET['firstName']) == " " && isset ($_GET['lastName']) == "Glover") {
echo "Hello";
}
}
if(isset($_GET['firstName'])&& isset($_GET['lastName'])){
if (isset($_GET['firstName']) == " " && isset($_GET['lastName']) == " ") {
echo "Hello";
}
}
?>
</html>
这不起作用的原因是:
if(isset($_GET['firstName'])&& isset($_GET['lastName'])){
echo $_GET['firstName']." ".$_GET['lastName'];
}
函数isset()
检查是否设置了变量(请参阅)。一旦您知道它已设置,您只需使用$\u GET
。您只需检查变量是否设置一次,因此可以将代码最小化为:
if (isset($_GET['firstName']) == "Kory" && isset($_GET['lastName']) == " ")
if (true or false) == "Kory" will never be true
isset
只会告诉您是否为变量设置了值。您不应该将其用于值比较。您正在将isset($\u GET['firstName'])
与其他字符串进行比较;但是它只会返回一个布尔值,所以比较永远不会成功
$firstName = $_GET["firstName"];
$lastName = $_GET["lastName"];
if (isset($_GET['firstName']) && isset($_GET['lastName'])) {
if ($firstName == "Kory" && $lastName == " ") {
echo "Hello Kory";
}
if ($firstName == " " && $lastName == "Glover") {
echo "Hello";
}
if ($firstName == " " && $lastName == " ") {
echo "Hello";
}
}