<html><body><script type="text/javascript">x=5+5;document.write(x);document.write("<br />");x="5"+"5";document.write(x);document.write("<br />");x=5+"5";document.write(x);document.write("<br />");x="5"+5;document.write(x);document.write("<br />");</script><h3>规则是：</h3><p><strong>如果把数字与字符串相加，结果将成为字符串。</strong></p></body></html>