jiaowochunge

function Captcha() {
  const CharSet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
  const canvas = document.createElement('canvas');
  canvas.width = 160;
  canvas.height = 50;

  const ctx = canvas.getContext("2d");

  function addCharToCanvas(ctx, char, index) {
    const fontSize = 30, x = 10, y = 40;