Whether it's the Pinterest-worthy rainbow layer cake depicted on a slouchy sweatshirt, an insulated food bag stamped #lunch, or a gizmo to snap the perfect selfie, social media is at the center of this year's back-to-school purchases.

But it's not just apparel doused with hashtags and foodie fashion driving this tech trend.

Still in the must-have running are laptops, smartphones, and tablets, as well as online-experience enhancers and cellphone cases.

Techno extras reign so supreme this back-to-school season that adult gadgets are being marketed under the same-themed umbrella: Hammermill introduced an app this month connecting smartphones to nearby printers so parents could print school permission slips on the go. And while it may be a stretch, Tough Tested's solar-powered battery is touted as an easy way to juice up while waiting for Junior to wrap up soccer practice.

"Technology has changed our social experience, and it's evident in how kids play, what they wear, and how we relate to them," said Christopher Byrne, a content director at Time to Play (ttpm.com), which conducts product reviews. "It's trendy and it's now, but like generations of school kids before them, it's based on the fundamental idea of #FOMO fear of missing out."

Of the total $26.5 billion that parents of elementary, middle, and high schoolers will spend on back-to-school shopping this year, $12.4 billion, or $313 per child, will go toward computer-related electronics and school supplies, according to the National Retail Federation in Washington. Those same parents will spend $9.1 billion on clothing, or $231 per child.

The change in back-to-school shopping focus from wardrobe to electronics and their accessories is one of the main reasons the season seems endless, instead of the traditional promotions from mid-August to late September.

When parents do shop for apparel, they are more likely to buy in-season sale items than preseason full-price ones. Dollars spent online are expected to increase a third over last year as well, and with so many deals offered throughout the year, parents will continue to spend.

With more schools instituting uniforms, clothes hold less importance, especially because stores are not likely to run out of all-season-appropriate khakis and polos.

"Over the past several years, back-to-school has moved up earlier and earlier," said Byrne, noting that it now typically starts the week after July 4th festivities and runs well into October. "By moving the season up, we've trained the consumer to wait. And they know, if they wait, prices will start being marked down right after Labor Day."

"Nobody has that big of a chunk of money to spend all at one time anymore, especially after the recession," said Caletha Crawford of Caletha Crawford Childrenswear Consulting in New York. "Weather patterns have changed, too, so as moms buy their corduroys closer to winter, she waits to buy her kids', too."

So what does a kid need to feel trendy at school and weekends this back-to-school season?

For boys, the season's style slam-dunks include sports-related apparel, especially anything with the Nike swoosh. Jeans are dark. Sweatpants are loose, but not loose enough to fall down. Baseball caps must have skater-straight brims. And the socks of choice, five years going, are still Nike Elites (or a reasonable facsimile).

"They like the bright colors," said Patrick Walsh, director of marketing at Villa, the sportswear store based in Philadelphia. "That also translates to what's on their feet in socks as well as sneakers."

Technology for boys is about amplifying their online experience hopefully for school-related DVDs and weekend video games. For their earphones, most kids are choosing Beats by Dr. Dre, which this year features a crop of new colors, including green, turquoise, and purple.

Pre-tween must-haves for girls run the fashion gamut, from sweet images like Elsa from Disney's Frozen to edgy mini-moto jackets and plaid skirts. Jewelry, especially necklaces, are personalized with tiny initials. And there is no such thing as too much arm candy.

However, the coolest items of the year are connected to social media: Instagram-popular images like Gummi Bears and macarons on lunch sacks and book bags.

"The little girls want to take snaps of everything," said Kate Schneider, manager of My Kids Korner store in Narberth, Penn.. "It's all food, food, food. The sweeter, the better."

Notebooks and pencils feature Twitter-friendly positive messages like "You Can Sit With Us" (as in, no bullying allowed here). Or, #OOTD (outfit of the day) will do, too.

Your 9-year-old may be too young for a smartphone of her own, but a baseball cap marked #CELFIE is right up her aspirational alley.

(c)2014 The Philadelphia Inquirer

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