Do you mean that you are getting an HTML file from which you have to extract the data? If that is the case, as far as I know, there is no standard way of extracting the data - because HTML is meant for displaying the data, not identifying it. The data in HTML may exist in table, or a table within table or at the top level document, or wherever. Thus there is no standard way to extract. If you know exactly where the data exists, and how the HTML you receive is formatted, you may write some java code to parse the HTML and extract the data, using String tokenizers. Just a little warning in using this tokenizing method - if the format of the HTML changes in a way that effects the data layout within, your parsing logic will fail. Obviously this will be a very flaky solution and you should use it only if you MUST.
On the other hand, if your client enters data in an HTML form and this form is being submitted, the data in the form can be retrieved in a webmethods service (that you will need to write), by specifying the input parameters in the service with same name as the inputs in the HTML form.