php does not query if the text box is empty
phpIt is very simple to determine whether a variable is empty, just use empty That’s it. The following demonstrates how to make the form content empty without querying.
1. First write the query form
Submit a wd to the server through get
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Document</title> </head> <body> <form action="a.php" method="get"> <input type="search" name="wd"> <input type="submit" value="查询"> </form> </body> </html>
2. Then make a judgment. The wd is the content of the text box. Use empty for empty judgment
<?php
if(!isset($_GET['wd'])) {
exit;
}
if (empty($_GET['wd'])) {
die('为空');
}
// 在这进行查询处理
echo '正在查询', $_GET['wd'], '...';
?>When the content of the text box is empty, the program will execute die and exit, and subsequent query statements will not be executed.
Effect:
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