How to determine if the form is not empty in php
php判断表单不为空的方法：首先创建一个php校验表单，并检测字段是否为空；然后创建后端文件“ErrorCheck.php”；最后通过trim函数去除字符串中的前后空字符即可。
本文操作环境：windows7系统、PHP7.1版，DELL G3电脑
php校验表单检测字段是否为空的方法
具体如下：
php校验表单，检测字段是否为空，当表单中有未填写的字段，则会显示错误信息。
<html> <body> <form METHOD="POST" ACTION="ErrorCheck.php"> <h1>Contact Information</h1> <label>Nickname:</label> <input TYPE="TEXT" NAME="nickname"> <label>Title:</label> <input TYPE="TEXT" NAME="title"> <br /> <input TYPE="SUBMIT" VALUE="Submit"> <br /> <input TYPE="RESET" VALUE="Clear the Form"> </form> </body> </html>
php后端代码，保存为： ErrorCheck.php
<html>
<body>
<?php
$errorcount=0;
if (!trim($_POST['nickname'])) {
echo "<br /><b>Nickname</b> is required.";
$errorcount++;
}
if (!trim($_POST['title'])) {
echo "<br /><b>Title</b> is required.";
$errorcount++;
}
if ($errors > 0)
echo "<br /><br />Please use your browser's back button " .
"to return to the form, and correct error(s)";
?>
</body>
</html>trim()函数可以去除字符串中的前后空字符
推荐学习：《PHP视频教程》
" " (ASCII 32 (0×20)), an ordinary space. "\t" (ASCII 9 (0×09)), a tab. "\n" (ASCII 10 (0x0A)), a new line (line feed). "\r" (ASCII 13 (0x0D)), a carriage return. "\0″ (ASCII 0 (0×00)), the NUL-byte. "\x0B" (ASCII 11 (0x0B)), a vertical tab.
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