Javascript, PhP and SEO Impact?

[bronxpad]

What are the Pro's and Con's of using Java Script and PHP in a site when factoring in SEO?

[AlanBleiweiss]

JavaScript is one of several technologies that offers severe limitations in search engines and their ability to properly see content, then just as important but often overlooked, properly and cleanly evaluate that content from an SEO perspective.

Specific considerations:

• Google does a "fair" job at discovering content passed through JavaScript (either on-page or at the code level)
• A "fair" job means it's hit and miss as to whether their system can actually find that content
• Whatever content the Google system CAN find via JavaScript is NOT necessarily able to be used to properly evaluate content intent, focus or relationship to other content

So - the best practices recommendation is if you want/need content to be found and properly evaluated by Google (or Bing) do NOT pass it through JavaScript.

And also, if you want to HIDE content from Google, don't assume you can successfully do so via JavaScript either.

As for PHP, its the most widely adopted and utilized web programming language out there.  The language by itself is essentially SEO neutral.  It's all in how a programmer utilized PHP that matters.  In the hands of a programmer that either truly understands SEO or collaborates closely with an SEO expert (who also understands the limitations/pitfalls that can arise with "bad" (SEO-unfriendly) PHP coding, it's a great language.

[AdamThompson]

Alan's answer is spot on.

Avoid javaScript or carefully follow best-practices so Google can crawl all content without reading javaScript. Alan is exactly right when he said: never count on Google crawling through your JavaScript to find content, but also never count on being able to hide anything from Google via JavaScript.

Whether you use PHP or not is not directly relevant. PHP is executed server-side, so Google never sees your PHP code and doesn't care. What matters is whether your programmer writes PHP code that will generate search friendly HTML code, url structure, etc.