By SHELLY BANJO, DANIEL LIPPMAN and EVERDEEN MASON

Wal-Mart Stores Inc. and Target Corp. reported strong Thanksgiving Day traffic in stores and online, noting that shoppers were focused on big-ticket electronic products.

The retailers didn't provide specific sales figures but tried to suggest that their decisions to open earlier on the holiday were successful. Wal-Mart and Target were among a number of retailers that opened on Thanksgiving Day--at 6 p.m. and 8 p.m., respectively--in an effort to boost struggling sales in a tight economy and keep up with online retailers.

Wal-Mart said it recorded more than 10 million register transactions between 6 p.m. and 10 p.m. Thursday in its stores and nearly 400 million page views that day on walmart.com. Target said sales were among the highest it had seen in a single day online, and it booked twice as many orders on its website as last year in the early hours when door-busters became available.

The annual ritual that is "Black Friday" persists, in some cases defying logic as well as the calendar. Shoppers ventured out Thursday to fight the lines and load up on gear--even though stores have been trotting out holiday deals since Halloween, most of the offerings are available online and many of the discounts are illusory bargains on goods designed to be cheap.

Wal-Mart said its electronics, such as big-screen TVs, iPad minis and new game systems Xbox One and PS4, were among the top sellers.

For the first time, the company offered wristbands for popular products. It also said it sold 2.8 million towels, 2 million televisions, 1.4 million tablets, 300,000 bicycles and 1.9 million dolls. Hand-held videogames and SLR digital cameras were some of the most popular items on Walmart.com.

Some of Target's best sellers include big-screen TVs, Nikon digital cameras, Beats by Dr. Dre headphones and the hand-held videogame system, Nintendo 3DS XL.

The push to open stores earlier on Thanksgiving sparked an outcry from some employees and traditionalists. Wal-Mart looked to stem some of that potential hostility and outlined plans Friday to offer its store employees who worked on Thanksgiving Day a 25% discount on an entire purchase on Dec. 5 and Dec. 6.

Department stores J.C. Penney Co. and Macy's Inc. were opening their doors on Thanksgiving for the first time, but they held off until 8 p.m.

Sears Holding Corp.'s Sears and Kmart stores, as well as Penney, had pledged to keep their doors open all night, with Penney offering snow globes to bleary-eyed shoppers who were still awake at 4 a.m. or woke up early to snag free swag.

At the flagship Toys "R" Us Inc. store in New York's Times Square, people were lined up for two blocks behind barricades, waiting to get into the store at the 5 p.m. opening. The store passed out Santa hats to waiting shoppers.

"We've been doing this the last three years because the kids get a great deal and get what they want for Christmas, and I don't have to come back until next year," said Julia Naccari, 45 years old, of Bay Ridge, Brooklyn. She was at the front of the line, having waited since 2:30 p.m. Thursday and was planning to have Thanksgiving dinner later in the evening.

Wal-Mart's wristband guarantee, for people in line from 6 p.m. to 7 p.m., attracted shoppers like Satish Nanabala, who said he didn't want to wait in line for hours for hot products if he wasn't guaranteed to get them.

"If I can get a deal without too much effort, then I'll come out, otherwise it's not worth it to stand in line for hours," said Mr. Nanabala, 38 years old, who was standing in line for an iPad at a Wal-Mart in Saddle Brook, N.J., shortly after 6 p.m. Thursday.

When he got to Wal-Mart, he ended up picking up an Hewlett-Packard laptop for $278, as well as a Lego set for his two-year-old twins.

"I don't really need another laptop and didn't plan on buying one, but it was a good price," he said.

Despite the activity at stores, there was early evidence that many stayed home to shop deals online. By 6 p.m. Thursday, Thanksgiving online sales had increased 10% this year over the same period last year, according to IBM Digital Analytics Benchmark, which tracks transactions at 800 U.S. retail sites.

About 140 million people are expected to shop over this holiday weekend, a decline from the 147 million who planned to do so last year, according to the National Retail Federation. The trade group said that nearly a quarter of the people it surveyed plan to shop on Thanksgiving Day. Shoppers spent about $60 billion during the Black Friday weekend last year and more than 40% of that spending occurred online, according to the federation.

This year, many retailers are offering the same set of door-buster deals online. Most prices on items like TV sets, tablets, and videogames at stores including Wal-Mart and Sears will be offered online as well as in stores, though the chains say availability is limited.

Indeed, by early Thursday afternoon, the website for Best Buy Co. said it was sold out online for some of its Black Friday door-buster specials, such as those on various brands of tablets.

The discounting expected by retailers this holiday season is seen cutting into their earnings. Earlier this month, Target cut its profit outlook in anticipation of holiday competition against aggressive discounts from Wal-Mart and other retailers such as Best Buy and Toys "R" Us Inc. Wal-Mart also cut its full-year profit for the second time earlier this month, predicting flat sales.

If retailers can book any sales growth in such an environment, it will likely come at the expense of their rivals. The late Thanksgiving is adding further pressure by removing a week of shopping between that holiday and Christmas.

Stephen Anteau arrived with a friend at the Best Buy in Paramus, N.J., hoping to buy a 42-inch Sharp television for $299 he saw advertised in the local paper. The 66-year-old wouldn't normally go out for Black Friday deals, but the earlier start time enticed him, so he swung by after having Thanksgiving dinner nearby with friends.

"We're not maniacs. We're normal," he said.

Some shoppers pushed up Thanksgiving dinner just to be able to come shop at stores like Wal-Mart that had started deals earlier this year. Alyise Hickman, 26 years old, said her family typically held Thanksgiving dinner at 6 p.m., but this year they moved it up to 2 p.m.

"We've never come shopping on Black Friday and usually say a prayer for people who have to work at stores like Wal-Mart on Thanksgiving, but I am strapped for cash and needed stuff for my new place," she said.

Paul Ziobro contributed to this article.

Write to Shelly Banjo at shelly.banjo@wsj.com and Daniel Lippman at daniel.lippman@wsj.com