例：

$a = ‘/a/b/c/d/e.php’;$b = ‘/a/b/12/34/c.php’;

二者的相对路径结果为：/a/b/12/34/../../c/d/e.php

//计算出$b相对于$a的相对路径:
function getRelativePath($a,$b){$returnPath = array(dirname($b));$arrA = explode('/', $a);$arrB = explode('/', $returnPath[0]);for($i= 0 ,$len = count($arrB);$i<$len;$i++){if ($arrA[$i]!=$arrB[$i]) {break;}}if ($len-$i>0) {$returnPath = array_merge($returnPath,array_fill(1,$len-$i, '..'));}$returnPath = array_merge($returnPath,array_slice($arrA, $i));// echo implode('/', $returnPath);return implode('/', $returnPath);
}