php校验表单，检测字段是否为空_PHP

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：&nbspErrorCheck.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



” ” (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.