如何设置JS文字打字动画播放一次后停止，不再循环？

你的打字动画反复循环的核心原因是代码没有设置播放终止条件：

• 原tick方法会无条件递归调用自身，每完成一段文本的「打字输入-完全删除」流程，就会累加loopNum切换到下一段文本
• 所有预设文本轮播完成后，代码会通过this.loopNum % this.toRotate.length的取余运算回到第一段文本，触发无限循环

你只需要修改TxtType.prototype.tick方法，增加终止判断即可，以下提供两种常用的停止效果，按需选择即可，HTML代码无需修改：

效果1：轮播完所有文本1次后，停在最后一段文本的展示状态（不删除最后一段） #

修改后的完整JavaScript代码如下：

var TxtType = function(el, toRotate, period) {
    this.toRotate = toRotate;
    this.el = el;
    this.loopNum = 0;
    this.period = parseInt(period, 10) || 2000;
    this.txt = '';
    this.tick();
    this.isDeleting = false;
};

TxtType.prototype.tick = function() {
    var i = this.loopNum % this.toRotate.length;
    var fullTxt = this.toRotate[i];

    if (this.isDeleting) {
        this.txt = fullTxt.substring(0, this.txt.length - 1);
    } else {
        this.txt = fullTxt.substring(0, this.txt.length + 1);
    }

    this.el.innerHTML = '<span class="wrap">'+this.txt+'</span>';

    var that = this;
    var delta = 200 - Math.random() * 100;

    if (this.isDeleting) { delta /= 2; }

    if (!this.isDeleting && this.txt === fullTxt) {
        // 新增判断：如果是最后一段文本，打完直接终止，不再删除
        if (i === this.toRotate.length - 1) {
            return;
        }
        delta = this.period;
        this.isDeleting = true;
    } else if (this.isDeleting && this.txt === '') {
        this.isDeleting = false;
        this.loopNum++;
        delta = 500;
    }

    setTimeout(function() {
        that.tick();
    }, delta);
};

window.onload = function() {
    var elements = document.getElementsByClassName('typewrite');
    for (var i=0; i<elements.length; i++) {
        var toRotate = elements[i].getAttribute('data-type');
        var period = elements[i].getAttribute('data-period');
        if (toRotate) {
          new TxtType(elements[i], JSON.parse(toRotate), period);
        }
    }
    // INJECT CSS
    var css = document.createElement("style");
    css.type = "text/css";
    css.innerHTML = ".typewrite > .wrap { border-right: 0.08em solid #f6fd96}";
    document.body.appendChild(css);
};

效果2：所有文本都完成「打完-删除」的完整流程1次后停止，最终显示空文本 #

修改后的完整JavaScript代码如下：

var TxtType = function(el, toRotate, period) {
    this.toRotate = toRotate;
    this.el = el;
    this.loopNum = 0;
    this.period = parseInt(period, 10) || 2000;
    this.txt = '';
    this.tick();
    this.isDeleting = false;
};

TxtType.prototype.tick = function() {
    var i = this.loopNum % this.toRotate.length;
    var fullTxt = this.toRotate[i];

    if (this.isDeleting) {
        this.txt = fullTxt.substring(0, this.txt.length - 1);
    } else {
        this.txt = fullTxt.substring(0, this.txt.length + 1);
    }

    this.el.innerHTML = '<span class="wrap">'+this.txt+'</span>';

    var that = this;
    var delta = 200 - Math.random() * 100;

    if (this.isDeleting) { delta /= 2; }

    if (!this.isDeleting && this.txt === fullTxt) {
        delta = this.period;
        this.isDeleting = true;
    } else if (this.isDeleting && this.txt === '') {
        this.isDeleting = false;
        this.loopNum++;
        // 新增判断：所有文本都完成一轮播放后直接终止
        if (this.loopNum >= this.toRotate.length) {
            return;
        }
        delta = 500;
    }

    setTimeout(function() {
        that.tick();
    }, delta);
};

window.onload = function() {
    var elements = document.getElementsByClassName('typewrite');
    for (var i=0; i<elements.length; i++) {
        var toRotate = elements[i].getAttribute('data-type');
        var period = elements[i].getAttribute('data-period');
        if (toRotate) {
          new TxtType(elements[i], JSON.parse(toRotate), period);
        }
    }
    // INJECT CSS
    var css = document.createElement("style");
    css.type = "text/css";
    css.innerHTML = ".typewrite > .wrap { border-right: 0.08em solid #f6fd96}";
    document.body.appendChild(css);
};

内容的提问来源于stack exchange，提问作者Maghiar Engelmann Bianca