function begin_check(){
    if (document.getElementById("begin").value == "") 
    { 
        window.alert("Please input the from station!");
        document.getElementById("begin").focus();
        return false;
    }
    if (document.getElementById("end").value == "")
    { 
        window.alert("Please input the to station!");
        document.getElementById("end").focus();
        return false;
    }
		return true;
}
function chezhan_check(){
	if (document.getElementById("chezhan").value == "") 
    { 
        window.alert("Please input the station!");
        document.getElementById("chezhan").focus();
        return false;
    }
		return true;
}
function checi_check(){
    if (document.getElementById("checi").value == "") 
    { 
        window.alert("Please input the train no.!");
        document.getElementById("checi").focus();
        return false;
    }
		return true;
}