$url = 'https://www.chemicalbook.com/Search.aspx?keyword='.$cas;             
       
       try{
           //超时时间
           $opts=array(
              "http"=>array(
              "method"=>"GET",
              "timeout"=>15
            ),
         );
         ////创建数据流上下文
         $context = stream_context_create($opts);
         $html = file_get_contents($url, false, $context);
         
         
         $dom = new \DOMDocument();         
         //汉字乱码,在LoadHTML 之前先 对应的转码就可以了         
         $html = mb_convert_encoding($html ,'HTML-ENTITIES',"UTF-8");
         @$dom->loadHTML($html);
         $dom->normalize();
         $xpath = new \DOMXPath($dom);
                  
         $lists = $xpath->query('/html/body//table[@id="mbox"]/tr');
                  
         $arr = [];
         foreach ($lists as $node) {
             $td = $xpath->query('./td//text()',$node);
             if(strpos($td[0]->nodeValue, 'CBNumber')!== false){
                $arr['CBNumber'] = $td[1]->nodeValue;
             }
             elseif(strpos($td[0]->nodeValue, '英文名称')!== false){
                $arr['en'] = $td[1]->nodeValue;
             }
             elseif(strpos($td[0]->nodeValue , '中文名称')!== false){
                $arr['cn'] = $td[1]->nodeValue;
             }
             elseif(strpos($td[0]->nodeValue , 'MF')!== false){
               $arr['mf'] = $td[1]->nodeValue;
             }
             elseif(strpos($td[0]->nodeValue , 'MW')!== false){
                $arr['mw'] = $td[1]->nodeValue;
             }
             elseif(strpos($td[0]->nodeValue , 'CAS')!== false){
                $arr['cas'] = $td[1]->nodeValue;
             }
          }
        //打印得出来的抓取内容的最终数组
        Log::info('arr', $arr);
       }catch (\Exception $e){
        Log::info('searchChemBook exception', [$e]);
    }