html5生成柱状图（条形图）

<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

          /*for(var row = 1; row <= grid_rows; row++){

            var y = row * cell_height;

            context.moveTo(0,y);

            context.lineTo(a_canvas.width, y);

          }*/

		  	//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_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>
html5生成柱状图（条形图）详细代码
运行结果：
html5生成柱状图（条形图）-LMLPHP 　　