html5中怎么生成柱状图效果，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
<html> <canvas id="a_canvas" width="1000" height="700"></canvas> <script> (function (){ window.addEventListener("load", function(){ var data = [1000,1300,2000,3000,2000,2000,1000,1500,2000,5000,1000,1000]; var xinforma = ['1月','2月','3月','4月','5月','6月','7月','8月','9月','10月','11月','12月']; // 获取上下文 var a_canvas = document.getElementById('a_canvas'); var context = a_canvas.getContext("2d"); // 绘制背景 var gradient = context.createLinearGradient(0,0,0,300); // gradient.addColorStop(0,"#e0e0e0"); //gradient.addColorStop(1,"#ffffff"); context.fillStyle = gradient; context.fillRect(0,0,a_canvas.width,a_canvas.height); var realheight = a_canvas.height-15; var realwidth = a_canvas.width-40; // 描绘边框 var grid_cols = data.length + 1; var grid_rows = 4; var cell_height = realheight / grid_rows; var cell_width = realwidth / grid_cols; context.lineWidth = 1; context.strokeStyle = "#a0a0a0"; // 结束边框描绘 context.beginPath(); // 准备画横线 //划横线 context.moveTo(0,realheight); context.lineTo(realwidth,realheight); //画竖线 context.moveTo(0,20); context.lineTo(0,realheight); context.lineWidth = 1; context.strokeStyle = "black"; context.stroke(); var max_v =0; for(var i = 0; i<data.length; i++){ if (data[i] > max_v) { max_v =data[i]}; } max_vmax_v = max_v * 1.1; // 将数据换算为坐标 var points = []; for( var i=0; i < data.length; i++){ var v= data[i]; var px = cell_width * (i +1); var py = realheight - realheight*(v / max_v); //alert(py); points.push({"x":px,"y":py}); } //绘制坐标图形 for(var i in points){ var p = points[i]; context.beginPath(); context.fillStyle="green"; context.fillRect(p.x,p.y,15,realheight-p.y); context.fill(); } //添加文字 for(var i in points) { var p = points[i]; context.beginPath(); context.fillStyle="black"; context.fillText(data[i], p.x + 1, p.y - 15); context.fillText(xinforma[i],p.x + 1,realheight+12); context.fillText('月份',realwidth,realheight+12); context.fillText('资金量',0,10); } },false); })(); </script> </html>
运行结果：
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