WordPress评论框添加输入内容礼花绽放及页面抖动效果

经常看到许多网站上当我们输入评论的时候会出现一些礼花绽放的效果，还有一些网站输入内容后网站页面会抖动起来，其实这些内容都是通过 JavaScript 代码来实现的，今天闲着无聊从网上筛选了一些代码，整理一下分享出来，希望能够帮助大家尽快实现这一功能。

核心JS代码

将以下代码复制下来新建一个 .js 格式的文档，并以 activate-power-mode.js 命名之。

(function webpackUniversalModuleDefinition(root, factory) {
    if (typeof exports === 'object' && typeof module === 'object') module.exports = factory();
    else if (typeof define === 'function' && define.amd) define([], factory);
    else if (typeof exports === 'object') exports["POWERMODE"] = factory();
    else root["POWERMODE"] = factory()
})(this,function() {
    return (function(modules) {
        var installedModules = {};
        function __webpack_require__(moduleId) {
            if (installedModules[moduleId]) return installedModules[moduleId].exports;
            var module = installedModules[moduleId] = {
                exports: {},
                id: moduleId,
                loaded: false
            };
            modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
            module.loaded = true;
            return module.exports
        }
        __webpack_require__.m = modules;
        __webpack_require__.c = installedModules;
        __webpack_require__.p = "";
        return __webpack_require__(0)
    })([function(module, exports, __webpack_require__) {
        'use strict';
        var canvas = document.createElement('canvas');
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;
        canvas.style.cssText = 'position:fixed;top:0;left:0;pointer-events:none;z-index:999999';
        window.addEventListener('resize',
        function() {
            canvas.width = window.innerWidth;
            canvas.height = window.innerHeight
        });
        document.body.appendChild(canvas);
        var context = canvas.getContext('2d');
        var particles = [];
        var particlePointer = 0;
        POWERMODE.shake = true;
        function getRandom(min, max) {
            return Math.random() * (max - min) + min
        }
        function getColor(el) {
            if (POWERMODE.colorful) {
                var u = getRandom(0, 360);
                return 'hsla(' + getRandom(u - 10, u + 10) + ', 100%, ' + getRandom(50, 80) + '%, ' + 1 + ')'
            } else {
                return window.getComputedStyle(el).color
            }
        }
        function getCaret() {
            var el = document.activeElement;
            var bcr;
            if (el.tagName === 'TEXTAREA' || (el.tagName === 'INPUT' && el.getAttribute('type') === 'text')) {
                var offset = __webpack_require__(1)(el, el.selectionStart);
                bcr = el.getBoundingClientRect();
                return {
                    x: offset.left + bcr.left,
                    y: offset.top + bcr.top,
                    color: getColor(el)
                }
            }
            var selection = window.getSelection();
            if (selection.rangeCount) {
                var range = selection.getRangeAt(0);
                var startNode = range.startContainer;
                if (startNode.nodeType === document.TEXT_NODE) {
                    startNode = startNode.parentNode
                }
                bcr = range.getBoundingClientRect();
                return {
                    x: bcr.left,
                    y: bcr.top,
                    color: getColor(startNode)
                }
            }
            return {
                x: 0,
                y: 0,
                color: 'transparent'
            }
        }
        function createParticle(x, y, color) {
            return {
                x: x,
                y: y,
                alpha: 1,
                color: color,
                velocity: {
                    x: -1 + Math.random() * 2,
                    y: -3.5 + Math.random() * 2
                }
            }
        }
        function POWERMODE() {
            {
                var caret = getCaret();
                var numParticles = 5 + Math.round(Math.random() * 10);
                while (numParticles--) {
                    particles[particlePointer] = createParticle(caret.x, caret.y, caret.color);
                    particlePointer = (particlePointer + 1) % 500
                }
            } {
                if (POWERMODE.shake) {
                    var intensity = 1 + 2 * Math.random();
                    var x = intensity * (Math.random() > 0.5 ? -1 : 1);
                    var y = intensity * (Math.random() > 0.5 ? -1 : 1);
                    document.body.style.marginLeft = x + 'px';
                    document.body.style.marginTop = y + 'px';
                    setTimeout(function() {
                        document.body.style.marginLeft = '';
                        document.body.style.marginTop = ''
                    },
                    75)
                }
            }
        };
        POWERMODE.colorful = false;
        function loop() {
            requestAnimationFrame(loop);
            context.clearRect(0, 0, canvas.width, canvas.height);
            for (var i = 0; i < particles.length; ++i) {
                var particle = particles[i];
                if (particle.alpha <= 0.1) continue;
                particle.velocity.y += 0.075;
                particle.x += particle.velocity.x;
                particle.y += particle.velocity.y;
                particle.alpha *= 0.96;
                context.globalAlpha = particle.alpha;
                context.fillStyle = particle.color;
                context.fillRect(Math.round(particle.x - 1.5), Math.round(particle.y - 1.5), 3, 3)
            }
        }
        requestAnimationFrame(loop);
        module.exports = POWERMODE
    },
    function(module, exports) { 
        (function() {
            var properties = ['direction', 'boxSizing', 'width', 'height', 'overflowX', 'overflowY', 'borderTopWidth', 'borderRightWidth', 'borderBottomWidth', 'borderLeftWidth', 'borderStyle', 'paddingTop', 'paddingRight', 'paddingBottom', 'paddingLeft', 'fontStyle', 'fontVariant', 'fontWeight', 'fontStretch', 'fontSize', 'fontSizeAdjust', 'lineHeight', 'fontFamily', 'textAlign', 'textTransform', 'textIndent', 'textDecoration', 'letterSpacing', 'wordSpacing', 'tabSize', 'MozTabSize'];
            var isFirefox = window.mozInnerScreenX != null;
            function getCaretCoordinates(element, position, options) {
                var debug = options && options.debug || false;
                if (debug) {
                    var el = document.querySelector('#input-textarea-caret-position-mirror-div');
                    if (el) {
                        el.parentNode.removeChild(el)
                    }
                }
                var div = document.createElement('div');
                div.id = 'input-textarea-caret-position-mirror-div';
                document.body.appendChild(div);
                var style = div.style;
                var computed = window.getComputedStyle ? getComputedStyle(element) : element.currentStyle;
                style.whiteSpace = 'pre-wrap';
                if (element.nodeName !== 'INPUT') style.wordWrap = 'break-word';
                style.position = 'absolute';
                if (!debug) style.visibility = 'hidden';
                properties.forEach(function(prop) {
                    style[prop] = computed[prop]
                });
                if (isFirefox) {
                    if (element.scrollHeight > parseInt(computed.height)) style.overflowY = 'scroll'
                } else {
                    style.overflow = 'hidden'
                }
                div.textContent = element.value.substring(0, position);
                if (element.nodeName === 'INPUT') div.textContent = div.textContent.replace(/\s/g, "\u00a0");
                var span = document.createElement('span');
                span.textContent = element.value.substring(position) || '.';
                div.appendChild(span);
                var coordinates = {
                    top: span.offsetTop + parseInt(computed['borderTopWidth']),
                    left: span.offsetLeft + parseInt(computed['borderLeftWidth'])
                };
                if (debug) {
                    span.style.backgroundColor = '#aaa'
                } else {
                    document.body.removeChild(div)
                }
                return coordinates
            }
            if (typeof module != "undefined" && typeof module.exports != "undefined") {
                module.exports = getCaretCoordinates
            } else {
                window.getCaretCoordinates = getCaretCoordinates
            }
        } ())
    }])
});

JS代码引入

将上面的核心代码保存成单一 js 文件后，将 activate-power-mode.js 文件丢到主题目录下任意位置（一般为主题的 js 文件夹中），记住该文件路径，将其替换为下面代码中的路径即可。然后将下面这段代码丢到主题的 footer.php 文件中即可。

<!-- 评论框礼花绽放效果-->
<script src="<?php bloginfo('template_directory'); ?>/diy/js/activate-power-mode.js "></script>
<script>
    POWERMODE.colorful = true; // ture 为启用礼花特效
    POWERMODE.shake = false; // false 为禁用震动特效
    document.body.addEventListener('input', POWERMODE);
</script>

代码中礼花绽放于页面震动效果可自主开启，大家根据自己需要开启即可。