[derbass]

Да-да, правильно. Сейчас код приложу.

$(document).ready(function() {
 
$("select#type").live("change", function() {
    var _this = this;
    chType(_this);
});

$("select#din").live("change", function() {
    var _this = this;
    chDin(_this);
});

$("select#diam").live("change", function() {
    var _this = this;
    chDiam(_this);
    //chVes(_this);
});

$("select#length").live("change", function() {
    var _this = this;
    chLength(_this);
    
    //chVes(_this);
});

$("input#rate").live("change", function() {
    var _this = this;
    chRate(_this);
});

$("input#ves").live("change", function() {
    var _this = this;
    chVes(_this);
});

function chType(_this) {
    var num = $(_this).attr('class').slice(1);
    var type = $(_this).val();
    $("select#din.n"+num).load("/ves/function.inc.php", {'action':'din','type':type}, function() {
        chDin($("select#din.n"+num));
    });
}

function chDin(_this) {
    var num = $(_this).attr('class').slice(1);
    var din = $(_this).val();
    $("select#diam.n"+num).load("/ves/function.inc.php", {'action':'diam','din':din}, function() {
        chDiam($("select#diam.n"+num));
    });
}

function chDiam(_this) {
    var num = $(_this).attr('class').slice(1);
    var din = $("select#din.n"+num).val();
    var diam = $(_this).val();
    $("select#length.n"+num).load("/ves/function.inc.php", {'action':'length','din':din,'diam':diam}, function(data) {
        if (data == '0') {
            $("select#length.n"+num).attr('disabled','disabled');
            //$("input#rate.n"+num).focus();
            $.post("/ves/function.inc.php", {'action':'wightnol','din':din,'diam':diam}, function(data) {
                $("input#wight.n"+num).val(data);
            });
        }
        else {
            $("select#length.n"+num).removeAttr('disabled');
        }
        chLength($("select#length.n"+num));
    });
}

function chLength(_this) {
    var num = $(_this).attr('class').slice(1);
    var din = $("select#din.n"+num).val();
    var diam = $("select#diam.n"+num).val();
    var length = $(_this).val();
    $.post("/ves/function.inc.php", {'action':'wight','din':din,'diam':diam,'length':length}, function(data) {
        $("input#wight.n"+num).val(data);
        chRate(_this);
    });
}

function chRate(_this) {
    var num = $(_this).attr('class').slice(1);
    var wight = $("input#wight.n"+num).val();
    var rate = $("input#rate.n"+num).val();
    var ves = (wight*rate).toFixed(5);
    $("input#ves.n"+num).val(ves);
}

function chVes(_this) {
    var num = $(_this).attr('class').slice(1);
    var wight = $("input#wight.n"+num).val();
    var ves = $("input#ves.n"+num).val();
    var rate = (ves/wight).toFixed(0);
    $("input#rate.n"+num).val(rate);
}

$("button#add").live("click", function() {
    var num = $(this).attr('class').slice(1);
    var newnum = parseInt(num)+1;
    $(this).hide();
    $.post("function.inc.php", {'action':'add','num':num}, function(data) {
        $("table#calc tbody").append(data);
        $("select#type.n"+newnum).focus();
    });
    if (num>1) {
        $("td.n"+num).html('<a class="delrow" href="javascript:void(0)" onclick="del('+num+')"></a>');
    }
});

function del(num) {
    var row = $("tr.n"+num);
    var rowprev = row.prev();
    var rownext = row.next().attr('class');
    var rowprevnum = parseInt(rowprev.attr('class').slice(1));
    row.remove();
    if (rowprevnum != '1') {
        $('td.n'+rowprevnum).html('<button id="add" class="n'+rowprevnum+'" onclick="return false;"></button><a class="delrow delrowfloat" href="javascript:void(0)" onclick="del('+rowprevnum+')"></a>');
    }
    else {
        if (!rownext) {
            $('td.n'+rowprevnum).html('<button id="add" class="n'+rowprevnum+'" onclick="return false;"></button>');
        }
    }
}