function resetField()
{
	var arg = resetField.arguments, form = document.forms[ arg[0] ];
	if( form.elements[ arg[1] ].value == arg[2] )
	{
		form.elements[ arg[1] ].value = '';
	}
}

function estMail(ch)
{
    return ch.indexOf("@")!=-1 ? ch.substring(ch.indexOf("@")).indexOf(".")!=-1 : false ;
}

function checkform()
{
	var variable ="", variable_en="";
	if (document.forms['testform'].nom.value.length!=0)
	{
		if (document.forms['testform'].tel.value.length!=0)
		{
			if (estMail(document.forms['testform'].email.value))
			{
				return true;
			}
			else
			{
				variable="'Email'";
				variable_en="'Email'";
			}
		}
		else
		{
			variable="'Tél'";
			variable_en="'Phone'";
		}
	}
	else
	{
		variable="'Nom'";
		variable_en="'Name'";
	}
    window.alert ("le champs "+variable+" n'est pas correct ou vide !! \n Field "+variable_en+" is either empty or of an incorrect format !!");
    return false;
}