function isValidEmail(str) {
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
}

function checkForm( form){
    
    var err=0;
    
    for( i= 0; i< form.elements.length; i++){
        if( jQuery( form.elements[i]).attr("params")== 'forced' && (form.elements[i].value=="" || form.elements[i].value== form.elements[i].defaultValue)){
            err++; 
        }
        if( jQuery( form.elements[i]).attr("name")=="mail") if( !isValidEmail( form.elements[i].value)) err++;            
    }    

    if( err>0){
        msg= "The details you have submitted are invalid. Please try again.\n";
        alert( msg);
        return false;
    }else return true;

}