javascript正弦曲线

var math = function() {    function T$(i) { return document.getElementById(i); }    var xlen = T$('content').clientWidth; x_posy = T$('content').clientHeight / 2, angle = 0;    function drawSine(amp) {        var self = this;        if (!(self instanceof drawSine)) {            return new drawSine(amp);        }         self.amp = amp;        self.initialize();    }    drawSine.prototype = {        initialize: function() {            var self = this;            self.drawXaxis();            self.drawYaxis();        },        drawXaxis: function() {            var self = this;            for (var i = 0, arr = []; i < xlen; ++i) {                arr[i] = self.createDot(1, 1, i, x_posy, '#213478');            }             T$('graph').innerHTML += arr.join('');        },        drawYaxis: function() {            var self = this, amp = self.amp;            for (var i = 0, arr = []; i < xlen; ++i) {                arr[i] = self.createDot(2, 2, i += amp, x_posy + Math.sin(angle+=.1) * x_posy, '#FF9933');            }             T$('graph').innerHTML += arr.join('');        },        createDot: function(w, h, x, y, c) {            return '<div style="width:'+w+'px;height:'+h+'px;font-size:0;background-color:'+c+';position:absolute;left:'+x+'px;top:'+y+'px;"><\/div>';        }    }    return {drawSine: drawSine}}();math.drawSine(2 /* 波长 */);

 显示一条正玄线