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>@H_301_4@ PHP后端代码，保存为： ErrorCheck.PHP/** * PHP校验表单，检测字段是否为空 * * @param * @arrange 512-笔记网： jb51.cc **/ <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> /*** 来自编程之家 jb51.cc（jb51.cc） ***/@H_301_4@ trim()函数可以去除字符串中的前后空字符/** * PHP校验表单，检测字段是否为空 * * @param * @arrange 512-笔记网： jb51.cc **/ ” ” (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. /*** 来自编程之家 jb51.cc（jb51.cc） ***/@H_301_4@
