js特效
# 一段js特效的代碼
# 使用方法:粘貼到頁腳代碼
<script type="text/javascript">! function() {//封裝方法,壓縮之后減少文件大小function get_attribute(node, attr, default_value) {return node.getAttribute(attr) || default_value;}//封裝方法,壓縮之后減少文件大小function get_by_tagname(name) {return document.getElementsByTagName(name);}//獲取配置參數function get_config_option() {var scripts = get_by_tagname("script"),script_len = scripts.length,script = scripts[script_len - 1]; //當前加載的scriptreturn {l: script_len, //長度,用于生成id用
z: get_attribute(script, "zIndex", -1), //z-index
o: get_attribute(script, "opacity", 0.5), //opacity
c: get_attribute(script, "color", "0,0,0"), //color
n: get_attribute(script, "count", 99) //count
};}//設置canvas的高寬function set_canvas_size() {canvas_width = the_canvas.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth,canvas_height = the_canvas.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;}//繪制過程function draw_canvas() {context.clearRect(0, 0, canvas_width, canvas_height);//隨機的線條和當前位置聯合數組var e, i, d, x_dist, y_dist, dist; //臨時節點//遍歷處理每一個點
random_points.forEach(function(r, idx) {r.x += r.xa,r.y += r.ya, //移動
r.xa *= r.x > canvas_width || r.x < 0 ? -1 : 1,r.ya *= r.y > canvas_height || r.y < 0 ? -1 : 1, //碰到邊界,反向反彈
context.fillRect(r.x - 0.5, r.y - 0.5, 1, 1); //繪制一個寬高為1的點//從下一個點開始for (i = idx + 1; i < all_array.length; i++) {e = all_array[i];// 當前點存在if (null !== e.x && null !== e.y) {x_dist = r.x - e.x; //x軸距離 l
y_dist = r.y - e.y; //y軸距離 n
dist = x_dist * x_dist + y_dist * y_dist; //總距離, m
dist < e.max && (e === current_point && dist >= e.max / 2 && (r.x -= 0.03 * x_dist, r.y -= 0.03 * y_dist), //靠近的時候加速
d = (e.max - dist) / e.max,context.beginPath(),context.lineWidth = d / 2,context.strokeStyle = "rgba(" + config.c + "," + (d + 0.2) + ")",context.moveTo(r.x, r.y),context.lineTo(e.x, e.y),context.stroke());}}}), frame_func(draw_canvas);}//創建畫布,并添加到body中var the_canvas = document.createElement("canvas"), //畫布
config = get_config_option(), //配置
canvas_id = "c_n" + config.l, //canvas id
context = the_canvas.getContext("2d"), canvas_width, canvas_height,frame_func = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(func) {window.setTimeout(func, 1000 / 45);}, random = Math.random,current_point = {x: null, //當前鼠標x
y: null, //當前鼠標y
max: 20000 // 圈半徑的平方
},all_array;the_canvas.id = canvas_id;the_canvas.style.cssText = "position:fixed;top:0;left:0;z-index:" + config.z + ";opacity:" + config.o;get_by_tagname("body")[0].appendChild(the_canvas);//初始化畫布大小
set_canvas_size();window.onresize = set_canvas_size;//當時鼠標位置存儲,離開的時候,釋放當前位置信息
window.onmousemove = function(e) {e = e || window.event;current_point.x = e.clientX;current_point.y = e.clientY;}, window.onmouseout = function() {current_point.x = null;current_point.y = null;};//隨機生成config.n條線位置信息for (var random_points = [], i = 0; config.n > i; i++) {var x = random() * canvas_width, //隨機位置
y = random() * canvas_height,xa = 2 * random() - 1, //隨機運動方向
ya = 2 * random() - 1;// 隨機點
random_points.push({x: x,y: y,xa: xa,ya: ya,max: 6000 //沾附距離
});}all_array = random_points.concat([current_point]);//0.1秒后繪制
setTimeout(function() {draw_canvas();}, 500);
}();
</script>
<canvas id="c_n5" width="1366" height="276" style="position: fixed; top: 0px; left: 0px; z-index: -1; opacity: 0.5;"></canvas>
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轉載于:https://www.cnblogs.com/52-qq/p/8544261.html
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