Keyword Density

   <?php
    function str_exists($item,$key,$keyword){
	 global $i;
	 if(preg_match("/$keyword/i",$item)){
	  $i++;
	 }
	}
	function clean_html($str){
	return preg_replace("/<\/[^>]+>|<[^\s]+\s|\'|\"|<[a-z]+>/i",'',$str);
	}

	function count_density($item,$key,$sum){
		if($item>0)
	  echo "
 $item times of $key, with the frequency of".number_format(($item/$sum)*100,2)."
";
	}

	$site=$_POST['site'];
	if(strpos($site,'http://')===false){
	 $site="http://".$site;
	}
	$keyword=trim($_POST['keyword']);
	
	$str=file_get_contents($site);
	$str1=clean_html($str);
    $a1=str_word_count($str1,1,$keyword);//获得所有的英语单词
    arsort($a1);
    $i=0;
	array_walk($a1,'str_exists',$keyword);
    $coo=count($a1);
	echo "$i times of $keyword,with the frequency of :".number_format(($i/$coo)*100,2).'%';