For the first time in about a decade, Angelica Talan did not brave the November cold for the holiday sales that many retailers launched on Thanksgiving this year.

Talan stayed in bed Thursday, hunting for discounts using the more than 50 new shopping apps she had download onto her iPad. By noon, she had hit pay dirt, snagging a gift for her sister at a deep discount.

“I decided not to fight the crowds this year,” said Talan, who runs the blog Clarendon Moms.

Even as millions of shoppers descended on retailers across the country Thursday, the battle for their dollars has shifted to the Web — specifically mobile devices — this holiday season.

Wal-Mart, Target, Best Buy and other big-box retailers have redesigned their mobile sites, launched new apps and are offering some consumers customized shopping experiences. A slow Web site may frustrate some shoppers, so retailers designed their pages for speed their year.

This approach to online shopping is a turnaround from last year, when big-box stores were still wary of “showrooming” — when customers visit a store and look for cheaper deals using their phones.

Now, they are embracing it as a way to drive sales to their own Web sites, analysts say. Target told its employees to approach customers using smartphones to browse for sales and steer them to the company’s mobile discounts.

Early indications show it may be working: As of 6 p.m., online sales jumped 10 percent this Thanksgiving, according to IBM Digital Analytics Benchmark. Mobile sales accounted for 23.5 percent of the total.

“There’s more opportunity to seize more revenue if you provide a great online experience,” said Steven Dykstra, senior product manager at Compuware APM, a firm that helps retailers measure the performance of their sites and apps and whose clients include Target, Sears, Best Buy and Amazon. (The Washington Post is owned by Amazon founder Jeffrey P. Bezos.)

Online shopping is growing, and a big chunk of that growth is from sales made on smartphones and tablets, analysts say. Surveys show that Americans are increasingly using their mobile devices to not just browse, but to make purchases, forcing retailers to pay attention. The average retailer can expect 14 percent of holiday sales to come from mobile devices, according to a report by Adobe Digital Analytics, an increase of 40 percent from a year ago. For some retailers, the share can be as high as 20 to 30 percent, analysts say.

That is significant in what is expected to be a lackluster holiday shopping season, analysts said. A short holiday season, lukewarm back-to-school sales and budget-conscious shoppers have raised the stakes for retailers, who are expecting a paltry 4 percent increase in sales this year, according to the National Retail Federation.

Many opened their doors earlier than ever this year — Toys R Us opened at 5 p.m. Thursday, while Wal-Mart and Best Buy followed an hour later — betting that the traditional Black Friday sales would not attract enough shoppers. Some retailers were offering such deep discounts that they worried it would squeeze profits.

Those discounts were enough for Yevette Lindsey, 58, who spent hours waiting outside a Best Buy in the District to buy a 55-inch television for her new house, while her husband stayed warm in the car. Lindsey, a retiree, said she didn’t mind coming out on Thanksgiving Day to shop. “It’s fine with me,” she said. “I give thanks every day.”

Shawnna Brown, 24, spent about seven hours perched on a metal chair outside the same store. The second-grade teacher hoped to snag an HP laptop that was discounted by $200. It was Brown’s first time venturing out for a Black Friday sale and she came prepared with a book, a packed lunch and a playlist. “I’m here for the experience,” she said.

Tina Zhu, 22, bought all of her holiday gifts online last year, but retailers reserved some deals for their brick-and-mortar stores. So Zhu was first in line outside the Target in the District on Thursday night to pick up an iPad air, which came with a $100 gift card, if you bought it in person.

For the consumers reluctant to leave the comforts of home on Thanksgiving, even for a deep discount, retailers are refining their Web strategy. That could make online sales, which are expected to jump 15 percent this year, the bright spot in an otherwise modest holiday season.

Chapin Traugott of Arlington has a Black Friday online shopping strategy already mapped out. “I’ve already bookmarked all the good deals,” she said.

Even so, Traugott ventured out to Toys R Us on Thursday afternoon for some early deals. “It’s kind of sad to be doing this on Thanksgiving,” said Traugott. “But the ads say 50 percent off — that’s a bigger discount than what you’d get online.”

And even as retailers experiment with technology, the scene at Kmart in Oxon Hill early Thursday was decidedly old school.

A manager emerged just before the store opened to hand out sheets of paper with coupons for popular electronics. The manager told the 40 or so well-bundled shoppers there was no need to run to get that TV or tablet — with that sheet of paper customers would have four hours to shop before having to pick the item up.

Denise Hickmon, 45, arrived at 3 a.m. and was the first person in line. A stack of coupons and advertisements in her hand, Hickmon said she saves for Black Friday sales all year — not an easy task with four children and only a medical disability paycheck to support them. She had her eye on an Android “ice cream” tablet for $39.99.

But the paper system — even for sought-after tech items — was fitting for a crowd that says shopping in the store was still the best way to go. Online shopping comes with too many risks, they said.

T. Littlejohn,who works at Prince George’s Animal Control, stayed up all night cooking before getting in line before the store opened Thursday morning. Online shopping, she said, just wouldn’t do. “I like to know what I’m getting, touch what I’m getting,” said Littlejohn.

Jeremy Borden contributed to this article.