Salesforce Web-To-Lead functionality offers an easy way to get the leads from your company websites or public websites (without any integrations) into Salesforce system. Web-To-Lead functionality in Salesforce generates a HTML Form which can be integrated in your company websites, using the HTML form we can captures the user entered data into Salesforce Lead records.
This Post & Video explained to debug your Salesforce Web-To-Lead HTML
Debug Your Salesforce Web-To-Lead HTML
This video explained to debug your salesforce web-to-lead html. Inorder to debug your html add the hidden field in your html.