On the fly keyword highlighting

Question

I have a PHP search script and I want to highlight the keywords that the user has searched with tags. How can I do this?

My code is:

if(!empty($_GET['q'])){
$keywords=explode(' ',$_GET['q']);
foreach($keywords as $query){
$query=mysql_real_escape_string($query);
$likes[]="keywords LIKE '%{$query}%'";
}

$searchResult=mysql_query("select * from questions where ".implode('or ',$likes)."limit 1");
while($row=mysql_fetch_assoc($searchResult)){
    $results="<div class='webresult'>{$row['result']}</div>";
}
}

Very similar to http://stackoverflow.com/questions/4081372/highlight-keywords-in-a-paragraph — Dan Blows, Jan 14 '12 at 16:12

jeroen · Accepted Answer · 2012-01-14T16:12:36.013

0

If $row['result'] does not contain html, you can do a string replace: replace all keywords in the result with <span class="highlight">keyword</span>

A simple example:

...
while($row=mysql_fetch_assoc($searchResult)) {
  $res = $row['result'];
  foreach($keywords as $kw) {
    $res = str_replace($kw, '<span class="highlight">' . htmlspecialchars($kw) . '</span>', $res);
  }
  $results="<div class='webresult'>{$res}</div>";
}
...

edited Jan 14 '12 at 16:12

answered Jan 14 '12 at 16:04

jeroen

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@Cosmo Posmo See Blowski's answer, but your search results are not reliable anyway as the visitor can enter for example an html tag as a search term. – jeroen Jan 14 '12 at 16:11
@Cosmo Posmo I have added the complete `while` loop for the mysql results. – jeroen Jan 14 '12 at 16:13
@Cosmo Posmo Sorry about that, just use `str_ireplace()` instead of `str_replace()` – jeroen Jan 14 '12 at 16:41

score 0 · Answer 2 · edited May 23 '17 at 12:03

0

Two solutions, depending on whether the result can contain HTML or not.

If the result can't contain HTML - use preg_replace. See here: highlight multiple keywords in search
If it can contain HTML, then you will need to use a DOM parser to separate text from HTML. Example parsers include Simple HTML Dom and DOMDocument.

edited May 23 '17 at 12:03

Community

1
1

answered Jan 14 '12 at 16:08

Dan Blows

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On the fly keyword highlighting

2 Answers2