php curl error simplehtmldom

Question

我使用php脚本使用curl登录网页，工作正常。然后我再加载两页并将它们存储到变量中。

curl_setopt($ch, CURLOPT_URL, $page1);
$resources = curl_exec($ch);

curl_setopt($ch, CURLOPT_URL, $page2);
$installations = curl_exec($ch);

我使用两个函数来处理$ page1和$ page 2中的数据

//Function findResourcesBuildings. Requires $page1
        function findResourcesBuildings($somepage)  {
            for ($i=1; $i < 10 ; $i++) { 
            $button = $i;
            $html = new simple_html_dom();
            $html->load($somepage, true, false);
            $result_tmp = preg_match_all('!\d+!', $html->find("li[id=button".$button."] span.level",0)->plaintext, $matches);
            $level = $matches[0][0];
            $state_char = $html->find("li[id=button".$button."]",0)->getAttribute('class');
            $state_title = $html->find("li[id=button".$button."] a",0)->title;
            $state = buildState($state_char,$state_title);
            $result[]=array('lvl'=>$level,'state'=>$state);
            }
        return $result;
        }

        //Function findInstallationsBuildings. Requires $page2
        function findInstallationsBuildings($somepage)  {
            for ($i=0; $i < 7 ; $i++) { 
            $button = $i;
            $html = new simple_html_dom();
            $html->load($somepage, true, false);
            $result_tmp = preg_match_all('!\d+!', $html->find("li[id=button".$button."] span.level",0)->plaintext, $matches);
            $level = $matches[0][0];
            $state_char = $html->find("li[id=button".$button."]",0)->getAttribute('class');
            $state_title = $html->find("li[id=button".$button."] a",0)->title;
            $state = buildState($state_char,$state_title);
            $result[]=array('lvl'=>$level,'state'=>$state);
            }
        return $result;
        }

$test = findResourcesBuildings($page1) //Works
$test2 = findInstallationsBuildings($page2) //  error: Call to a member function getAttribute() on a non-object

或

$test = findInstallationsBuildings($page2) //Works
$test2 = findResourcesBuildings($page1)  //  error: Call to a member function getAttribute() on a non-object

错误在这一行：

$state_char = $html->find("li[id=button".$button."]",0)->getAttribute('class');

但正如我上面所述，无论顺序如何，第二个变量都失败了。

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可能会发生什么？我迷失在这里。 感谢