function getPageCharset()
    {
        var charset = 'windows-1251';
        var metaTags = document.getElementsByTagName('meta');
        if(!metaTags) return charset;

        for(var i=0; i < metaTags.length; i++) {
            var meta = metaTags[i];
            if(!meta.httpEquiv || !meta.content) continue;
            var list = meta.content.split(';');
            for(var j=0; j < list.length; j++) {
                var it = list[j].replace(/\s+$/, '').replace(/^\s+/, '');
                var pos = it.indexOf('charset=');
                if(pos == -1) continue;
                charset = it.substr(pos+8).replace(/\s+$/, '').replace(/^\s+/, '');
                break;
            }
            break;
        }
        return charset;
    }    
        
    function checkForm( form ) {
        if( form.message.value.length == 0 ) {
            alert( 'Message must not be empty' );
            return false;
        }
        
        var hidden = document.createElement('input');
        hidden.type = 'hidden';
        hidden.name = 'charset';
        hidden.value = getPageCharset();
        form.appendChild( hidden );
        
        return true;
    }