SOURCE

function cssStyle2DomStyle(sName) {
    var res = ''
    var first = true
    sName.replace(/(\w+)/g, function () {
        console.log(arguments[0])
        if (first) {
            res += arguments[0]
            first = false
        } else {
            res += (arguments[0].slice(0, 1)).toUpperCase() + arguments[0].slice(1)
        }
    })

    return res
}
console.log(cssStyle2DomStyle('font-size'))