function trim(s){return s.replace(/(^\s*)|(\s*$)/g, "");}

function checkLogin(){
	if(trim(document.formLogin.username.value)==""){
		alert("用户名不能为空");
		document.formLogin.username.focus();
		return false;
	}
	if(trim(document.formLogin.password.value)==""){
		alert("密码不能为空");
		document.formLogin.password.focus();
		return false;
	}
	return true;
}

function show_info(s){
	if(s==1){
		document.getElementById('book1').style.display="block";
		document.getElementById('book2').style.display="none";
		document.getElementById('book3').style.display="none";
		document.getElementById('book4').style.display="none";
		document.getElementById('m001').className="bookin2";
		document.getElementById('m002').className="bookin";
		document.getElementById('m003').className="bookin";
		document.getElementById('m004').className="bookin";
		}
	else if(s==2){
		document.getElementById('book1').style.display="none";
		document.getElementById('book2').style.display="block";
		document.getElementById('book3').style.display="none";
		document.getElementById('book4').style.display="none";
		document.getElementById('m001').className="bookin";
		document.getElementById('m002').className="bookin2";
		document.getElementById('m003').className="bookin";
		document.getElementById('m004').className="bookin";
		}
	else if(s==3){
		document.getElementById('book1').style.display="none";
		document.getElementById('book2').style.display="none";
		document.getElementById('book3').style.display="block";
		document.getElementById('book4').style.display="none";
		document.getElementById('m001').className="bookin";
		document.getElementById('m002').className="bookin";
		document.getElementById('m003').className="bookin2";
		document.getElementById('m004').className="bookin";
		}
	else if(s==4){
		document.getElementById('book1').style.display="none";
		document.getElementById('book2').style.display="none";
		document.getElementById('book3').style.display="none";
		document.getElementById('book4').style.display="block";
		document.getElementById('m001').className="bookin";
		document.getElementById('m002').className="bookin";
		document.getElementById('m003').className="bookin";
		document.getElementById('m004').className="bookin2";
		}
	}