If indie rock band Imagine Dragons has become accustom to the scrum of crazed fans and sold-out shows, you wouldn’t know it. Frontman Dan Reynolds looked downright giddy bouncing onto the stage at The Complex on Friday night.

“I can honestly say there wouldn’t be Imagine Dragons if it wasn’t for the support from Utah — from the very beginning,” Reynolds said during the set.

Maybe it felt like a bit of a homecoming for him. After all, the Las Vegas-native attended BYU, as did guitarist Wayne Sermon (of American Fork), before attending Berklee College of Music. It was there in Boston that Sermon met and persuaded bassist Ben McKee and drummer Daniel Platzman to join him and Reynolds in Vegas. That was only a few years ago.

Earning a grassroots following after independently releasing three EPs, the band recently signed with Interscope and released their debut album “Night Visions" in September at No. 2 on the Billboard album charts, with the lead single "It’s Time."

Imagine Dragons lacks much classification but its sound appeals to just about everyone — and everyone seems to want a snippet of it in their movie, trailer or ad.

Despite its whirlwind success and the surrounding commercial clamor, Reynolds is reverent in reminding fans it’s all about the music.

“I never thought I’d be on stage or anything like that; I was always on the other end. I loved coming to concerts and letting the world just shut off for a little while,” he said. “This really doesn’t have anything to do with us. We’re just regular people — we just love to make music.”

The band pinballs from folk-infused foot-stomping rhythmic anthems (“It’s Time”) to grinding electric-rock numbers like “Radioactive” that are catchy enough to appeal to pop fans and heavy enough for hard-rockers. All the while, they’ve managed to create a sound-stamp that threads their songs together.

The stage Friday night gave way to massive tree silhouettes, swirling backdrops and monster drums used most effectively during their hit-single “Radioactive.” The vocal talents of 2,500 fans backed up just about every number in the set — highly addictive songs including the above mentioned as well as “Bleeding Out,” “Tiptoe,” “Demons, “Hear Me” and “Nothing Left to Say.”

Opening Acts: Australian rock band Atlas Genius, and LA rock band Nico Vega