function check(theForm) { if(theForm.UserName.value=='') { alert("请输入用户名"); theForm.UserName.focus(); return false; } if(theForm.Password.value=='') { alert("请输入密码"); theForm.Password.focus(); return false; } } function showhide(id,visible) { if(visible) document.getElementById(id).style.display=""; else document.getElementById(id).style.display="none"; } document.write('
');