function isRightString(s)
{
	var c;
	for(i=0;i<s.length;i++)
	{
		c=s.substr(i,1);
		if(!(isChar(c)) && !(isNumber(c)) && (c!='_') && (c!='-') && (c!='.') && (c!="@"))
		{
			return false;
		}  
	}
	return true;
}
function isChar(c)
{
	if(((c>='a')&&(c<='z')) || ((c>='A')&&(c<='Z')))
	{
		return true;
	}
	else
	{
		return false;
	}
}
function isNumber(c)
{
	if((c>='0')&&(c<='9'))
	{
		return true;
	}
	else
	{
		return false;
	}
}

function isRightStr4Email(email) 
{ 	
	if(email.length <= 8)
	{
		return false;
	}
	if(!isRightString(email))
	{
		return false;
	}
	if(email.indexOf("@") == -1 || email.indexOf("@") == 0)
	{
		return false;
	}
	if(email.lastIndexOf("@") >= (email.length - 4))
	{
		return false;
	}
	if(email.indexOf(".") == -1 || email.indexOf(".") == 0)
	{
		return false;
	}
	if(email.lastIndexOf(".") >= (email.length - 2))
	{
		return false;
	}
	if(email.substring(email.indexOf("@"),email.length).indexOf(".") == -1)
	{
		return false;
	}
	if(email.substring(email.indexOf("@")+1,(email.indexOf("@")+2)) == ".")
	{
		return false;
	}
	
	var ch;
	var j = 0;
	for(i=0;i<email.length;i++)
	{
		ch=email.substr(i,1);
		if(ch == "@")
		{
			j++;
		}  
	}
	if(j != 1)
	{
		return false;
	}

	return true;
}