彩虹字

let angle = 0;
let p = document.querySelector('p');
let text = p.textContent.split('');
let len = text.length;
let phaseJump = 360 / len;
let spans;

p.innerHTML = text.map(function (char) {
    return '<span>' + char + '</span>';
}).join('');

spans = p.children;
(function wheee() {
    for (var i = 0; i < len; i++) {
        spans[i].style.color = 'hsl(' + (angle + Math.floor(i * phaseJump)) + ', 55%, 70%)';
    }
    angle++;
    requestAnimationFrame(wheee);
})();

<p>拼搏过的人生，即便没有成功。也只是不完美，但是它完整!</p>

<style>
    p {
        position: absolute;
        top: 45%;
        left: 50%;
        width: 50%;
        margin: 0;
        font: 26px "PT Serif", serif;
        -webkit-transform-origin: 0 0;
        -ms-transform-origin: 0 0;
        transform-origin: 0 0;
        -webkit-transform: translate(-50%, -50%);
        -ms-transform: translate(-50%, -50%);
        transform: translate(-50%, -50%);
    }

    p::first-letter {
        float: left;
        margin-right: 9px;
        line-height: 1em;
        font-size: 260%;
    }

    p::after {
        content: "";
        display: inline-block;
        width: 100%;
    }
</style>