Do you ever try checking your HTML code for error? If no then you are probably writing wrong HTML code. This will cause your HTML load slow on browser. Validate your HTML code according to your document type defined in <!DOCTYPE ..>
These are free W3C Markup Validation Services which checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards.
Validation is a process of checking your documents against a formal Standard, such as those published by the World Wide Web Consortium (W3C) for HTML and XML-derived Web document types, or by the WapForum for WML, etc. It serves a similar purpose to spell checking and proofreading for grammar and syntax, but is much more precise and reliable than any of those processes because it is dealing with precisely-specified machine languages, not with nebulously-defined human natural language.
Non-valid pages are (by definition) relying on error-correction by a browser. This error correction can and does vary radically across different browsers and versions, so that many authors who unwittingly relied on the quirks of Netscape 1.1 (for example) suddenly found their pages appeared totally blank in Netscape 2.0.
Other services link provided here are:
RSS/Atom feeds, CSS stylesheets, to find broken links.
Here you can validate your markup by these methods:
Validate by URL,
Validate by File Upload, or
Validate by Direct Input.
You can validate your markup using url if your file is online. You can save your local file source code and upload your file for validation.
Other Links for doing these Job:
You can install this extension in you Firefox Browser for HTML validation.
Firefox Html Validator
You may like this: Online HTML code Preview