如何给前台模版加个用户登陆区块

<form name="k_formlist" method="post" id="k_formlist" action="login.php"><div class="k_htm"><label>会员名</label><p><input class="k_in w150" type="text" name="username" value="" maxlength="15" /><tt><tt><a href="javascript:; " class="k_user_register">立即注册</a></tt></tt></p></div><div class="k_htm"><label>密码</label><p><input class="k_in w150" type="password" name="userpass" maxlength="30" /><tt><tt><a href="javascript:;" class="k_user_lostpwd">忘记密码</a></tt></tt></p></div><div class="k_htm"><label>登录有效期</label><p><span><input type="radio" name="expire" id="k_expire_0" value="0" /><label for="k_expire_0">浏览器进程</label><input type="radio" name="expire" id="k_expire_86400" value="86400" /><label for="k_expire_86400">一天</label><input type="radio" name="expire" id="k_expire_2592000" value="2592000" checked="true" /><label for="k_expire_2592000">一月</label><input type="radio" name="expire" id="k_expire_15768000" value="15768000" /><label for="k_expire_15768000">半年</label><input type="radio" name="expire" id="k_expire_31536000" value="31536000" /><label for="k_expire_31536000">一年</label><input type="radio" name="expire" id="k_expire_315360000" value="315360000" /><label for="k_expire_315360000">永久</label></span></p></div><div class="k_htm"><label>验证码</label><p><input type="text" maxlength="4" class="k_verify k_in w50" name="k_verify" id="k_verify"/></p></div><input type="hidden" name="k_verify_salt" id="k_verify_salt" /><input type="hidden" name="re" id="re" value=""/><p class="k_submit"><inp