Help with loop

[Targa]

Im using the script below to total lines on an invoice.
There are 3 fields per line: Line_Qty(n), Line_Unit_Price(n) and
Line_Item_Subtotal(n).
It works when there is a fixed number of lines but I need to have it work
for any amount of lines.

Can somebody help me convert this into a loop?

Thanks in advance!

function calc(form) {
var sum = 0;
var rowsum;
var quantity = 1

// Add Lines
if ( parseFloat(form.Line_Qty1.value) &&
parseFloat(form.Line_Unit_Price1.value) ) {
quantity += parseInt(form.Line_Qty1.value);
form.Line_Qty1.value = parseInt(form.Line_Qty1.value);
form.Line_Unit_Price1.value = parseFloat(form.Line_Unit_Price1.value);
rowsum = form.Line_Qty1.value * form.Line_Unit_Price1.value;
sum += rowsum;
form.Line_Unit_Price1.value = money(form.Line_Unit_Price1.value);
form.Line_Item_Subtotal1.value = money(rowsum)
}
if ( parseFloat(form.Line_Qty2.value) &&
parseFloat(form.Line_Unit_Price2.value) ) {
quantity += parseInt(form.Line_Qty2.value);
form.Line_Qty2.value = parseInt(form.Line_Qty2.value);
form.Line_Unit_Price2.value = parseFloat(form.Line_Unit_Price2.value);
rowsum = form.Line_Qty2.value * form.Line_Unit_Price2.value;
sum += rowsum;
form.Line_Unit_Price2.value = money(form.Line_Unit_Price2.value);
form.Line_Item_Subtotal2.value = money(rowsum)
}
if ( parseFloat(form.Line_Qty3.value) &&
parseFloat(form.Line_Unit_Price3.value) ) {
quantity += parseInt(form.Line_Qty3.value);
form.Line_Qty3.value = parseInt(form.Line_Qty3.value);
form.Line_Unit_Price3.value = parseFloat(form.Line_Unit_Price3.value);
rowsum = form.Line_Qty3.value * form.Line_Unit_Price3.value;
sum += rowsum;
form.Line_Unit_Price3.value = money(form.Line_Unit_Price3.value);
form.Line_Item_Subtotal3.value = money(rowsum)
}
and so on......

 

[Shawn Milo]

Im using the script below to total lines on an invoice.
There are 3 fields per line: Line_Qty(n), Line_Unit_Price(n) and
Line_Item_Subtotal(n).
It works when there is a fixed number of lines but I need to have it work
for any amount of lines.

Can somebody help me convert this into a loop?

<snip>


Try something like this (untested).
Some people would say that using
eval() is a bad thing, so maybe
one of them will take the time to post an
alternative.

Shawn


// -- code follows -- //

var lineNum = 1;

var qty;
var prc;
var subt;

qty = eval('form.Line_Qty' + lineNum);
prc = eval('form.Line_Unit_Price' + lineNum);
subt = eval('form.Line_Subtotal' + lineNum);

while (qty.value){

if ( parseFloat(qty.value) && parseFloat(prc.value) ) {
quantity += parseInt(qty.value);
qty.value = parseInt(qty.value);
prc.value = parseFloat(prc.value);
rowsum = qty.value * prc.value;
sum += rowsum;
prc.value = money(prc.value);
subt.value = money(rowsum)
}


lineNum++;
qty = eval('form.Line_Qty' + lineNum);
prc = eval('form.Line_Unit_Price' + lineNum);
subt = eval('form.Line_Subtotal' + lineNum);

}

// -- end of code -- //

 

[Richard Cornford]

Shawn Milo wrote:

Try something like this (untested).
Some people would say that using
eval() is a bad thing, so maybe
one of them will take the time to post an
alternative.

OK:-

qty = eval('form.Line_Qty' + lineNum);

qty = form['Line_Qty' + lineNum];

prc = eval('form.Line_Unit_Price' + lineNum);

prc = form['Line_Unit_Price' + lineNum];

subt = eval('form.Line_Subtotal' + lineNum);

subt = form['Line_Subtotal' + lineNum];

qty = eval('form.Line_Qty' + lineNum);

qty = form['Line_Qty' + lineNum];

prc = eval('form.Line_Unit_Price' + lineNum);

prc = form['Line_Unit_Price' + lineNum];

subt = eval('form.Line_Subtotal' + lineNum);

subt = form['Line_Subtotal' + lineNum];

<URL: http://jibbering.com/faq/#FAQ4_39 >

In this context the alternative to - eval - is the standard bracket
notation property accessor syntax, supported in every javascript
version, shorter, simpler and between two and twenty times faster
depending on the browser (and unlike - eval - is not optional in ECMA
327 "Compact Profile" implementations so it will also work in more
browsers).

The reason that - eval - is considered a bad thing is that it really is
the _worst_ way of doing 99.99% of the things that are done with it.

Richard.

 

[Lee]

Targa said:

form.Line_Qty1.value = parseInt(form.Line_Qty1.value);
form.Line_Unit_Price1.value = parseFloat(form.Line_Unit_Price1.value);
rowsum = form.Line_Qty1.value * form.Line_Unit_Price1.value;

Those first two lines are doing nothing useful.
The value attribute of a form element is *always* a string.

You're parsing the numeric values out of those strings,
storing them back into the value attributes, which causes
the engine to automatically convert them back to strings,
then multiplying those strings, which causes them to be
automatically converted back to numbers.

 

[Targa]

Hey! Looks like youve got me on the right track!

But now I get 'undefined' is null or not an object.

How can I track this buggar down?

Shawn Milo wrote:

Try something like this (untested).
Some people would say that using
eval() is a bad thing, so maybe
one of them will take the time to post an
alternative.

OK:-

qty = eval('form.Line_Qty' + lineNum);

qty = form['Line_Qty' + lineNum];

prc = eval('form.Line_Unit_Price' + lineNum);

prc = form['Line_Unit_Price' + lineNum];

subt = eval('form.Line_Subtotal' + lineNum);

subt = form['Line_Subtotal' + lineNum];

qty = eval('form.Line_Qty' + lineNum);

qty = form['Line_Qty' + lineNum];

prc = eval('form.Line_Unit_Price' + lineNum);

prc = form['Line_Unit_Price' + lineNum];

subt = eval('form.Line_Subtotal' + lineNum);

subt = form['Line_Subtotal' + lineNum];

<URL: http://jibbering.com/faq/#FAQ4_39 >

In this context the alternative to - eval - is the standard bracket
notation property accessor syntax, supported in every javascript
version, shorter, simpler and between two and twenty times faster
depending on the browser (and unlike - eval - is not optional in ECMA
327 "Compact Profile" implementations so it will also work in more
browsers).

The reason that - eval - is considered a bad thing is that it really is
the _worst_ way of doing 99.99% of the things that are done with it.

Richard.

 

[Donald F. McLean]

Targa said:




Those first two lines are doing nothing useful.
The value attribute of a form element is *always* a string.

I'm not convinced that's entirely true - it does cause the values
to be normalized.

You're parsing the numeric values out of those strings,
storing them back into the value attributes, which causes
the engine to automatically convert them back to strings,
then multiplying those strings, which causes them to be
automatically converted back to numbers.

Assuming that we want the values in the fields to be normalized, is it
less efficient to use the code above or something like this:

var quantity = parseInt(form.Line_Qty1.value);
form.Line_Qty1.value = quantity;

var value = parseFloat(form.Line_Unit_Price1.value);
form.Line_Unit_Price1.value = value;

rowsum = quantity * value;

I'm guessing that it probably doesn't matter that much.

Donald

 

[Targa]

Actually, the loop Shawn provided is working (with Richard's mod)
Each line totals up fine. I think its the next step (totaling all the lines)
that's tripping me up:

var total=0;
var form = document.forms["calculations"];
for (var i=1; i<=<%= RS("myTotal")%>; i++) {
total += (form["Line_Item_Subtotal"+i].value-0);
}
form.subtotal.value = money(total);

On page load I get 'undefined' is null or not an object.
Once I hit the calc button, I get 'value' is null or not an object.

It always returns the wrong line # so I dont know to to trace it.

Complete code:
<SCRIPT LANGUAGE="JavaScript"><!--
// INVOICE CALCULATIONS
function calc(form) {
var sum = 0;
var rowsum;
var quantity = 1;
var lineNumber = 1;

var qty;
var prc;
var subt;
qty = form['Line_Qty' + lineNumber];
prc = form['Line_Unit_Price' + lineNumber];
subt = form['Line_Item_Subtotal' + lineNumber];

while (qty.value){

if ( parseFloat(qty.value) && parseFloat(prc.value) ) {
quantity += parseInt(qty.value);
qty.value = parseInt(qty.value);
prc.value = parseFloat(prc.value);
rowsum = qty.value * prc.value;
sum += rowsum;
prc.value = money(prc.value);
subt.value = money(rowsum)
}

lineNumber++;
qty = form['Line_Qty' + lineNumber];
prc = form['Line_Unit_Price' + lineNumber];
subt = form['Line_Item_Subtotal' + lineNumber];

}

var total=0;
var form = document.forms["calculations"];
for (var i=1; i<=<%= RS("myTotal")%>; i++) {
total += (form["Line_Item_Subtotal"+i].value-0);
}
function money(num) // converts from floating point to money format
{
var amount = Math.abs(num);
var pounds = Math.floor(amount);
var pence = Math.round( 100*(amount-pounds) );
if(pence>99) pence=0, pounds++;
pence += ""
while (pence.length < 2) pence = "0" + pence;
amount = pounds + "." + pence;
if (num < 0) return "[" + amount + "]";
return amount;
}

//-->
</SCRIPT>

Hey! Looks like youve got me on the right track!

But now I get 'undefined' is null or not an object.

How can I track this buggar down?

Shawn Milo wrote:

Try something like this (untested).
Some people would say that using
eval() is a bad thing, so maybe
one of them will take the time to post an
alternative.

OK:-

qty = eval('form.Line_Qty' + lineNum);

qty = form['Line_Qty' + lineNum];

prc = eval('form.Line_Unit_Price' + lineNum);

prc = form['Line_Unit_Price' + lineNum];

subt = eval('form.Line_Subtotal' + lineNum);

subt = form['Line_Subtotal' + lineNum];

qty = eval('form.Line_Qty' + lineNum);

qty = form['Line_Qty' + lineNum];

prc = eval('form.Line_Unit_Price' + lineNum);

prc = form['Line_Unit_Price' + lineNum];

subt = eval('form.Line_Subtotal' + lineNum);

subt = form['Line_Subtotal' + lineNum];

<URL: http://jibbering.com/faq/#FAQ4_39 >

In this context the alternative to - eval - is the standard bracket
notation property accessor syntax, supported in every javascript
version, shorter, simpler and between two and twenty times faster
depending on the browser (and unlike - eval - is not optional in ECMA
327 "Compact Profile" implementations so it will also work in more
browsers).

The reason that - eval - is considered a bad thing is that it really is
the _worst_ way of doing 99.99% of the things that are done with it.

Richard.

 

[Lee]

Donald F. McLean said:

I'm not convinced that's entirely true - it does cause the values
to be normalized.

That's why I said "nothing useful", rather than absolutely nothing.
Note that it will change a price entered as "2.10" to "2.1", which
is probably not what they really want.