我想在php的网页中输出php语句，就如我要在一个网页中输出下面的代码
<?php
echo"welcome!";
?>
怎么做才行了，我是这样用的，可是不行
<?php
echo"<?php";
echo"welcom";
echo"?>";
?>
输出的只有“welcome",没有了php的标签

用反斜线"\"将尖括号等php符号变为引用，参考：
http://cn.php.net/manual/zh/language.references.spot.php
主要参考该手册中这个例子：
[php]
<?php
  class y {
   public $d;
  }

  $A = new y;
  $A->d = 18;
  echo "Object \$A before operation:\n";
  var_dump($A);

  $B = $A; // This is not an explicit (=&) reference assignment,
           // however, $A and $B refer to the same instance
           // though they are not equivalent names
  $C =& $A; // Explicit reference assignment, $A and $C refer to
           // the same instance and they have become equivalent
           // names of the same instance

  $B->d = 1234;

  echo "\nObject \$B after operation:\n";
  var_dump($B);
  echo "\nObject \$A implicitly modified after operation:\n";
  var_dump($A);
  echo "\nObject \$C implicitly modified after operation:\n";
  var_dump($C);

  // Let's make $A refer to another instance
  $A = new y;
  $A->d = 25200;
  echo "\nObject \$B after \$A modification:\n";
  var_dump($B); // $B doesn't change
  echo "\nObject \$A after \$A modification:\n";
  var_dump($A);
  echo "\nObject \$C implicitly modified after \$A modification:\n";
  var_dump($C); // $C changes as $A changes
?>
[php]
我没有验证过，你可以试试。