<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>canvas</title> <script type="text/javascript" src="../js/jQuery.js"></script> <style type="text/css"> *{ margin: 0; padding: 0; outline: none; border: none; } #canvas{ width: 7rem; margin: .25rem 0 0 1.5rem; border: 1px solid black; } </style> </head> <body> <canvas id="canvas" width="1000" height="600"></canvas> </body> </html> <script type="text/javascript"> /** * rem 布局初始化 */ $('html').css('font-size', $(window).width()/10); /** * 獲取 canvas 畫布 * 獲取 canvas 繪圖上下文環境 */ var canvas = $('#canvas')[0]; var cxt = canvas.getContext('2d'); /** * 文字的度量 * measureText(字符串) * 注意在使用前設置好對應的 font 屬性才能准確獲取文字的長度 */ cxt.fillStyle = "blue"; cxt.font = "bold 40px sans-serif"; var textWidth = cxt.measureText("Hello Canvas"); alert(textWidth.width); </script>