Question

Hi i am trying to get just the numbers from a html string and append them to a URL which is then wrote to the page as a example:

<p id="catId">cat number 2301254187</p>
<script type="text/javascript">
        var itemId = document.getElementById('catId').innerHTML;
        var links = '<a href="http://www.test.com' + catId + '">Go to Catergory</a>';
        document.write(links);

Ive tried something like above which works but i get the whole of the contents of the p tag. Im pretty new to this and im guessing that regular expressions need to be used to extract the numbers only?

Answer 1

You were right about needing to use a regular expression.

<p id="catId">cat number 2301254187</p>
<script type="text/javascript">
    var itemId = document.getElementById('catId').innerHTML.match(/\d+/);

    if (itemId.length) {
        var links = '<a href="http://www.test.com' + itemId[0] + '">Go to Catergory</a>';
        document.write(links);
    }
</script>

See the match() method