var prefixes=new Array();

prefixes["_nonempty_"]=validate_nonempty;
prefixes["_email_"]=validate_email;
prefixes["_date_"]=validate_date;
prefixes["_time_"]=validate_time;
prefixes["_datetime_"]=validate_datetime;
prefixes["_number_"]=validate_number;

warnings=new Array();
warnings["_nonempty_"]="You must enter a e-mail !";
warnings["_email_"]="There appears to be something wrong with e-mail address. Please try once again.";
warnings["_date_"]=" ";
warnings["_time_"]=" ";
warnings["_datetime_"]=" ";
warnings["_number_"]=" ";
var GetPrefixPos=0;

function CheckMandatoryFields(form) {
	var f=document.forms[form];
	var prefix;
	var c;
	var i;
	var flag=true;
	for(c=0;c<f.elements.length;c++) {
		while((prefix=getNextPrefix(f.elements[c].name))!="") {
			if(!(prefixes[prefix](f.elements[c]))) {
				alert(warnings[prefix]);
				f.elements[c].focus();
				GetPrefixPos=0;
				return false;
			}
		}
	}
	
	while(flag) {
		flag=false;
		for(c=0;c<f.elements.length;c++) {
			for(prefix in prefixes) {
				if(f.elements[c].name.substring(0,prefix.length)==prefix) {
					f.elements[c].name=f.elements[c].name.substring(prefix.length,f.elements[c].name.length);
					flag=true;
				}
			}
		}
	} 
	return true;
}

function getNextPrefix(name) {
	var prefix;
	for(prefix in prefixes) {
		if(name.substring(GetPrefixPos,GetPrefixPos+prefix.length)==prefix) {
			GetPrefixPos+=prefix.length;
			return prefix;
		}
	}
	GetPrefixPos=0;
	prefix="";
	return prefix;
}

function validate_email(obj) {
	var i;
	var val=obj.value;
	var state=0;
	if(val=="") return true;
	for(i=0;i<val.length;i++) {
		// alert("state="+state+" val["+i+"]="+val.charAt(i));
		switch(state) {
			case 0: // waiting @
				if(val.charAt(i)=="@") {
					state=1;
				} else { 
					if(!is_alnum(val.charAt(i))) return false;
				}
				break;
			case 1: // waiting .
				if(val.charAt(i)==".") {
					state=2;
				} else {
					if(!is_alnum(val.charAt(i))) return false;
				}
				break;
			case 2: // waiting for some chars... or .
				if(is_alnum(val.charAt(i))) {
					state=1;
				} else {
					return false;
				}
				break;
		}
	}
	if(state==1) return true;
	return false;
}
			
function validate_date(obj) {
	var i,state=0;
	var val=obj.value;
	var dd="",mm="",yyyy="";
	if(val=="") return true;
	for(i=0;i<val.length;i++) {
		switch(state) {
			case 0:
				if(val.charAt(i)=="-") state=1;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else dd+=val.charAt(i);
				break;
			case 1:
				if(val.charAt(i)=="-") state=2;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else mm+=val.charAt(i);
				break;
			case 2:
				if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else yyyy+=val.charAt(i);
		}
	}
	if(state!=2) return false;
	if(isNaN(parseInt(dd)) || isNaN(parseInt(mm)) || isNaN(parseInt(yyyy))) return false;
	if(parseInt(dd) < 0 || parseInt(mm) < 0 || parseInt(dd) > 31 || parseInt(mm) > 12) return false;
	if(yyyy.length!=4) return false;
	return true;
}

function validate_time(obj) {
	var i,state=0;
	var val=obj.value;
	var hh="",mi="";
	if(val=="") return true;
	for(i=0;i<val.length;i++) {
		switch(state) {
			case 0:
				if(val.charAt(i)==":") state=1;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else hh+=val.charAt(i);
				break;
			case 1:
				if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else mi+=val.charAt(i);
		}
	}
	if(state!=1) return false;
	if(isNaN(parseInt(hh)) || isNaN(parseInt(mi))) return false;
	if(parseInt(hh)>23 || parseInt(mi)<0 || parseInt(mi)>59 || parseInt(mi)<0) return false;
	return true;
}


function validate_datetime(obj) {
	var i,state=0;
	var val=obj.value;
	var dd="",mm="",yyyy="",hh="",mi="";
	if(val=="") return true;
	for(i=0;i<val.length;i++) {
		switch(state) {
			case 0:
				if(val.charAt(i)=="-") state=1;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else dd+=val.charAt(i);
				break;
			case 1:
				if(val.charAt(i)=="-") state=2;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else mm+=val.charAt(i);
				break;
			case 2:
				if(val.charAt(i)==" ") state=3;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else yyyy+=val.charAt(i);
				break;
			case 3:
				if(val.charAt(i)==":") state=4;
				else if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else hh+=val.charAt(i);
				break;
			case 4:
				if("0123456789".indexOf(val.charAt(i))==-1) return false;
				else mi+=val.charAt(i);
		}
	}
	if(state!=4) return false;
	
	if(isNaN(parseInt(dd)) || isNaN(parseInt(mm)) || isNaN(parseInt(yyyy))) return false;
	if(parseInt(dd) < 0 || parseInt(mm) < 0 || parseInt(dd) > 31 || parseInt(mm) > 12) return false;
	if(isNaN(parseInt(hh)) || isNaN(parseInt(mi))) return false;
	if(parseInt(hh)>23 || parseInt(mi)<0 || parseInt(mi)>59 || parseInt(mi)<0) return false;
	if(yyyy.length!=4) return false;
	return true;
}

function validate_nonempty(obj) {
	var val=obj.value;
	if(val=="") return false;
	return true;
}

function validate_number(obj) {
	var val=obj.value;
	if(val=="") return true;
	if(isNaN(parseFloat(val))) return false;
	return true;
}

function is_alpha(c) {
	if("qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM_.-".indexOf(c)!=-1) return true;
	return false;
}

function is_number(c) {
	if("0123456789".indexOf(c)!=-1) return true;
	else return false;
}

function is_alnum(c) {
	if(is_alpha(c) || is_number(c)) return true;
	return false;
}