例 1.1 onblur和onfocus马克-to-win：onblur失去焦点和onfocus得到焦点事件。
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.0 Transitional//EN”><HTML><head><meta http-equiv=”content-type” content=”text/html; charset=utf-8″/><SCRIPT LANGUAGE=”JavaScript”><!–function check(a){var username = a.value;if (username == “”){/*String.fontcolor() (Method)Encapsulates the string within an <FONT COLOR=”…”> tag context.*/document.getElementById(“error”).innerHTML = “用户名不能为空！”.fontcolor(“red”);}}function rese(){document.getElementById(“error”).innerHTML = “”;}//–></SCRIPT></HEAD><BODY onload=”document.getElementById(‘u’).focus()”>
