要计算文本宽度，请使用JavaScript中的Canvas.measureText()方法。您可以尝试运行以下代码以获取文本宽度-
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<script>
function displayTextWidth(text, font) {
var myCanvas = displayTextWidth.canvas || (displayTextWidth.canvas = document.createElement("canvas"));
var context = myCanvas.getContext("2d");
context.font = font;
var metrics = context.measureText(text);
return metrics.width;
};
document.write("Text Width: "+displayTextWidth("这是演示文字！", "italic 18pt verdana")); //
</script>
</body>
</html>