MENLO PARK, Calif. — Silicon Valley, it turns out, doesn’t revolve around the stock prices of Facebook and its playful sidekick, Zynga.

By most indications, tech companies in this hub of innovation are humming along, even as two of its rising stars endure steep declines in their stock prices that have wiped out more than $60 billion in wealth in the past six months.

Companies catering to mobile devices, business software and data management products are thriving, while longtime Silicon Valley stalwarts such as Apple Inc. and Google Inc. remain among the most revered brands in the world.

“Nothing has fundamentally changed about the opportunities that are possible,” says Aaron Levie, CEO of Box, an online data-storage company based in Los Altos, Calif.

The optimism in Silicon Valley can be seen in a variety of ways in this area that covers roughly 40 miles from San Jose to San Francisco:

Entrepreneurs are still pursuing big ideas and raising millions of dollars.

Silicon Valley startups raised $3.2 billion from venture capitalists during the April-June quarter, far more than in any other part of the U.S., as tracked by the National Venture Capital Association. Venture capital flowing into Silicon Valley increased by 4 percent from the same time last year, while it dropped 12 percent nationwide.

Apartment rents in San Francisco have soared beyond the lofty levels of the original Internet boom more than a decade ago. This time, it’s being driven by well-paid software engineers and Web designers who are flocking to Silicon Valley.

Computer-coding programmers still command top dollar for their services because there aren’t enough of them to meet demand.

Jeremy Stoppelman, CEO of the 8-year-old online reviews service Yelp Inc., said his company is always behind on its hiring goals for software engineers.

“There is no one who is like, ‘Oh, we have all the engineers we need, and we don’t need more,’ ” he says. Competition is fierce from all sides – massive companies such as Google and Facebook, tiny startup incubators and everything in between.

“And there is attrition,” Stoppelman says. “From what I gather from engineers, two, three times a week they get calls from recruiters.”

Software engineers working in the San Francisco area are now paid an average of about $115,000, up from $106,000 in 2008, according to Glassdoor.com, which analyzed compensation figures collected from users. The average salary for software engineers in the Bay Area is about 17 percent higher than the national average for the same occupation, according to Glassdoor.

Google now pays its engineers an average of $142,000, up from just under $104,000 in 2008, Glassdoor calculated. During that time, Google’s workforce has swelled by 70 percent to about 34,000 employees, including thousands of engineers working at or near its headquarters in Mountain View, Calif.

Even Facebook and Zynga remain on hiring sprees.

Good vibes

Echoing an oft-repeated Silicon Valley ethos, Levie says startups are much more focused on their long-term prospects than their performance from one quarter to the next.

Wall Street, though, isn’t known for its patience. Investors’ fixation on short-term results has left Facebook’s stock trading at about half of its initial public offering price, while Zynga’s stock has lost more than two-thirds of its value.

“The challenge of the public markets is that it has the ability to create a lot of these near-term distractions if you start paying attention to the day-to-day stock price changes,” Levie says. “A lot of those day-to-day changes have no bearing or relevance on the ultimate opportunity for your business.”

Facebook has consistently declined to talk about its stock price. But CFO David Ebersman told analysts in July that “obviously we’re disappointed about how the stock has traded.”

Zynga Inc., the maker of “FarmVille,” “Mafia Wars” and other games that first became popular on Facebook, appears to face more uncertainty.

The San Francisco company is losing money and players while facing stiff competition as more games are played on mobile devices instead of personal computers. CEO Mark Pincus insists the company will rebound, though many analysts consider Zynga hopelessly adrift. Zynga’s shares are now hovering around $3, down from a peak of nearly $16 in early March.

Nonetheless, there are nothing but good vibes emanating from many other technology companies in Silicon Valley and San Francisco.

Even as Zynga employees watch the value of their stock options deflate, the 65 or so workers at Pinterest are settling in to the online scrapbooking service’s new San Francisco headquarters just a block away. Around the same time Facebook went public, Pinterest raised $100 million from investors who valued the company at $1.5 billion, according to several media reports.