my function needs a for loop.

A

Abby Lee

My function works but there has got to be a way to make a for loop to
handle this...but I can't get a for loop to work. You can tell, I'm
not very good at this...help.

"myvalue" is the number of miles the person enters
"myitem" is the row...there are seven rows where they can list
expenses.
"myvalue" * .375 = amount to be reimbursed
All the rows are added and placed into the total.


function autoReimb(myvalue,myitem){
var nrow = "autoReimb" + myitem;
if(isPositiveInteger(myvalue.value)){
var amount = myvalue.value * .375;
formatedamt = format(amount)
eval("document.forms[0]." + nrow + ".value = formatedamt");
if(isPositiveInteger(document.forms[0].miles1.value))
var reimb1 = document.forms[0].autoReimb1.value;
else var reimb1 = 0;
if(isPositiveInteger(document.forms[0].miles2.value))
var reimb2 = document.forms[0].autoReimb2.value;
else var reimb2 = 0;
if(isPositiveInteger(document.forms[0].miles3.value))
var reimb3 = document.forms[0].autoReimb3.value;
else var reimb3 = 0;
if(isPositiveInteger(document.forms[0].miles4.value))
var reimb4 = document.forms[0].autoReimb4.value;
else var reimb4 = 0;
if(isPositiveInteger(document.forms[0].miles5.value))
var reimb5 = document.forms[0].autoReimb5.value;
else var reimb5 = 0;
if(isPositiveInteger(document.forms[0].miles6.value))
var reimb6 = document.forms[0].autoReimb6.value;
else var reimb6 = 0;
if(isPositiveInteger(document.forms[0].miles5.value))
var reimb7 = document.forms[0].autoReimb7.value;
else var reimb7 = 0;

var totalauto = (reimb1 * 1) + (reimb2 * 1) + (reimb3 * 1) + (reimb4
* 1) + (reimb5 * 1) + (reimb6 * 1) + (reimb7 * 1);
document.forms[0].autotot.value = format(totalauto);
}
else eval("document.forms[0]." + nrow + ".value = ''");
} //End Function
 
M

McKirahan

Abby Lee said:
My function works but there has got to be a way to make a for loop to
handle this...but I can't get a for loop to work. You can tell, I'm
not very good at this...help.

"myvalue" is the number of miles the person enters
"myitem" is the row...there are seven rows where they can list
expenses.
"myvalue" * .375 = amount to be reimbursed
All the rows are added and placed into the total.


function autoReimb(myvalue,myitem){
var nrow = "autoReimb" + myitem;
if(isPositiveInteger(myvalue.value)){
var amount = myvalue.value * .375;
formatedamt = format(amount)
eval("document.forms[0]." + nrow + ".value = formatedamt");
if(isPositiveInteger(document.forms[0].miles1.value))
var reimb1 = document.forms[0].autoReimb1.value;
else var reimb1 = 0;
if(isPositiveInteger(document.forms[0].miles2.value))
var reimb2 = document.forms[0].autoReimb2.value;
else var reimb2 = 0;
if(isPositiveInteger(document.forms[0].miles3.value))
var reimb3 = document.forms[0].autoReimb3.value;
else var reimb3 = 0;
if(isPositiveInteger(document.forms[0].miles4.value))
var reimb4 = document.forms[0].autoReimb4.value;
else var reimb4 = 0;
if(isPositiveInteger(document.forms[0].miles5.value))
var reimb5 = document.forms[0].autoReimb5.value;
else var reimb5 = 0;
if(isPositiveInteger(document.forms[0].miles6.value))
var reimb6 = document.forms[0].autoReimb6.value;
else var reimb6 = 0;
if(isPositiveInteger(document.forms[0].miles5.value))
var reimb7 = document.forms[0].autoReimb7.value;
else var reimb7 = 0;

var totalauto = (reimb1 * 1) + (reimb2 * 1) + (reimb3 * 1) + (reimb4
* 1) + (reimb5 * 1) + (reimb6 * 1) + (reimb7 * 1);
document.forms[0].autotot.value = format(totalauto);
}
else eval("document.forms[0]." + nrow + ".value = ''");
} //End Function
Click to expand...


1) Use "document.getElementById" not "eval()".

2) You have "document.forms[0].miles5.value" twice;
instead on "document.forms[0].miles7.value"

3) You should use "myvalue" not "myvalue.value".

4) It would have been easier to help you if you had included the <form>.

5) It can be cleaned up a lot more but the following works; watch for
word-wrap.

<html>
<head>
<title>mileage.htm</title>
<script type="text/javascript">
/*
* My function works but there has got to be a way to make a for loop to
* handle this...but I can't get a for loop to work. You can tell, I'm
* not very good at this...help.
*
* "myvalue" is the number of miles the person enters
* "myitem" is the row...there are seven rows where they can list expenses.
* "myvalue" * .375 = amount to be reimbursed
* All the rows are added and placed into the total.
*
*/

function validate() {
// autoReimb(20,2)
for (var i=1; i<8; i++) {
autoReimb(document.getElementById("miles"+i).value,i)
}
}

function autoReimb(myvalue,myitem){
var nrow = "autoReimb" + myitem;
if(isPositiveInteger(myvalue)){
var amount = myvalue * .375;
formatedamt = format(amount)
//eval("document.forms[0]." + nrow + ".value = formatedamt");
document.getElementById(nrow).value = formatedamt;
if(isPositiveInteger(document.forms[0].miles1.value))
var reimb1 = document.forms[0].autoReimb1.value;
else var reimb1 = 0;
if(isPositiveInteger(document.forms[0].miles2.value))
var reimb2 = document.forms[0].autoReimb2.value;
else var reimb2 = 0;
if(isPositiveInteger(document.forms[0].miles3.value))
var reimb3 = document.forms[0].autoReimb3.value;
else var reimb3 = 0;
if(isPositiveInteger(document.forms[0].miles4.value))
var reimb4 = document.forms[0].autoReimb4.value;
else var reimb4 = 0;
if(isPositiveInteger(document.forms[0].miles5.value))
var reimb5 = document.forms[0].autoReimb5.value;
else var reimb5 = 0;
if(isPositiveInteger(document.forms[0].miles6.value))
var reimb6 = document.forms[0].autoReimb6.value;
else var reimb6 = 0;
if(isPositiveInteger(document.forms[0].miles7.value))
var reimb7 = document.forms[0].autoReimb7.value;
else var reimb7 = 0;
var totalauto = (reimb1 * 1) + (reimb2 * 1) + (reimb3 * 1) + (reimb4
* 1) + (reimb5 * 1) + (reimb6 * 1) + (reimb7 * 1);
document.forms[0].autotot.value = format(totalauto);
}
//else eval("document.forms[0]." + nrow + ".value = ''");
else document.getElementById(nrow).value = "";
}
function format(amount) {
// { your code }
return amount;
}
function isPositiveInteger () {
// { your code }
return true;
}
</script>
<style type="text/css">
..rite { text-align:right; width:40px }
</style>
</head>
<body>
<form>
<br><input type="text" name="miles1" value="10" class="rite">
= <input type="text" name="autoReimb1" value="" class="rite">
<br><input type="text" name="miles2" value="20" class="rite">
= <input type="text" name="autoReimb2" value="" class="rite">
<br><input type="text" name="miles3" value="30" class="rite">
= <input type="text" name="autoReimb3" value="" class="rite">
<br><input type="text" name="miles4" value="40" class="rite">
= <input type="text" name="autoReimb4" value="" class="rite">
<br><input type="text" name="miles5" value="50" class="rite">
= <input type="text" name="autoReimb5" value="" class="rite">
<br><input type="text" name="miles6" value="60" class="rite">
= <input type="text" name="autoReimb6" value="" class="rite">
<br><input type="text" name="miles7" value="70" class="rite">
= <input type="text" name="autoReimb7" value="" class="rite">
<br><input type="text" name="autotot">
<input type="button" value="Calc" onclick="validate()">
</form>
</body>
</html>
 
M

Michael Winter

[snip]
1) Use "document.getElementById" not "eval()".
Click to expand...

Why? Neither is the optimum solution (though gEBI is better).

document.forms[0].elements['miles' + n].value

gEBI requires a recent browser. The line above doesn't.

[snip]
3) You should use "myvalue" not "myvalue.value".
Click to expand...

It would appear that myvalue is a form control that contains a number. If
it were an actual number, undefined would result from the property access.

[snip]
5) It can be cleaned up a lot more but the following works; watch for
word-wrap.
Click to expand...

Yes, it could.

[snip]

function isPosInt(v) {
return /^0|([1-9]\d*)$/.test(v);
}

function autoReimb(val, itm) {
var e = document.forms[0].elements,
r = 'autoReimb' + itm,
t = 0;

if(isPosInt(val.value)) {
e[r].value = format(val.value * 0.375);
for(var i = 1; i <= 7; ++i) {
if(isPosInt(e['miles' + i].value)) {
t += +e['autoReimb' + i].value;
}
}
e['autotot'].value = format(t);
} else {
e[r].value = '';
}
}

To the OP:

Untested, but it's what I believe it's you were after.

Hope that helps,
Mike
 
M

McKirahan

Michael Winter said:
[snip]
1) Use "document.getElementById" not "eval()".
Click to expand...

Why? Neither is the optimum solution (though gEBI is better).

document.forms[0].elements['miles' + n].value

gEBI requires a recent browser. The line above doesn't.
http://www.jibbering.com/faq/#FAQ4_40
[snip]

3) You should use "myvalue" not "myvalue.value".
Click to expand...

It would appear that myvalue is a form control that contains a number. If
it were an actual number, undefined would result from the property access.
Click to expand...

"myvalue" is a input parameter to the function:

function autoReimb(myvalue,myitem){
[snip]
5) It can be cleaned up a lot more but the following works; watch for
word-wrap.
Click to expand...

Yes, it could.

[snip]

function isPosInt(v) {
return /^0|([1-9]\d*)$/.test(v);
}

function autoReimb(val, itm) {
var e = document.forms[0].elements,
r = 'autoReimb' + itm,
t = 0;

if(isPosInt(val.value)) {
e[r].value = format(val.value * 0.375);
for(var i = 1; i <= 7; ++i) {
if(isPosInt(e['miles' + i].value)) {
t += +e['autoReimb' + i].value;
}
}
e['autotot'].value = format(t);
} else {
e[r].value = '';
}
}
Click to expand...

Good suggestion!
 
M

Michael Winter

[snip]
document.forms[0].elements['miles' + n].value

gEBI requires a recent browser. The line above doesn't.
Click to expand...

http://www.jibbering.com/faq/#FAQ4_40
Click to expand...

What's that meant to imply?

[snip]
"myvalue" is a input parameter to the function:
Click to expand...

I know. However, the OP's original code suggests that it is a reference to
a form element, not an actual value. If it were a value, myvalue.value
would evaluate to undefined and I'm sure that if the OP made that mistake,
it would have been explicitly mentioned ("Why does myvalue.value not give
me the value I passed?") or corrected before posting to the group.

If I'm wrong, then you were correct in your first post in that the OP
should have shown the actual function call on the FORM element.

[snip]

Mike
 
M

McKirahan

Michael Winter said:
[snip]
document.forms[0].elements['miles' + n].value

gEBI requires a recent browser. The line above doesn't.
Click to expand...

http://www.jibbering.com/faq/#FAQ4_40
Click to expand...

What's that meant to imply?

[snip]
Click to expand...

Anytime eval() usage is brought up in this ng it gets jumped on.

Here's a recent post which discusses "Why is 'eval' evil?".

From: Lasse Reichstein Nielsen ([email protected])
Subject: Re: Why is 'eval' evil?
View: Complete Thread (8 articles)
Original Format
Newsgroups: comp.lang.javascript
Date: 2004-04-04 16:06:50 PST


Reply Via Newsgroup said:
I don't use eval alot in my scripts - but I do use it - and since I
always out to learn more / improve my javascript skills, I'm curious
why something I thought 'normal' would be considered abnormal.

Can someone put some meat on the bones of 'eval' - its advantages (if
any) and its disadvantages (which seem great).
Click to expand...

As you might guess, it's not the first time someone has questionend
the "eval is evil" slogan :) It even made the FAQ.
<URL:http://jibbering.com/faq/#FAQ4_40>

The short argument for not using eval is:
"It's shooting pidgeons with cannons."
Sure, it get's the job done, but it's harder to control and takes a
lot more resources than needed, and when it fails, it fails
spectacularly (read: blows up in your face).

There is (almost) no situation where there isn't another method that
also does the job, and both more efficiently and a lot safer.

With "more efficient" I mean that it uses fewer resources. The "eval"
function works by first turning its argument into a string, then it
parses the string as a Javascript program and finally it evaluates
it. This is a very expensive operation, and the generality of it is
only needed in rare cases that most people writing web pages will
never meet.

With "safer" I mean that it it is less likely to fail spectacularly.
Since eval can execute arbitrary Javascript expressions, passing the
wrong argument can cause arbitrary errors. On a server, using eval on
a user supplied string is a *very* bad idea. On a client, the main
problem is that the error message is harder to connect to the actual
error, and that, e.g., syntax errors in eval'ed code will only be
detected at run time, not when the script is loaded. So: eval
both introduces more possible errors and hides existing errors.

The two most common (mis)uses of eval are:
1) converting strings to numbers.
There are plenty of dedicated functions and operators for just this
problem: parseInt, parseFloat, Number, the prefix plus operator, most
mathematical operators (string*1,string/1,string-0). Of these, the
prefix plus is the fastest by a small margin. It is roughly *50* times
faster than using eval (in my browser).

2) accessing properties using a computed name.
Example:
eval("document.images.img"+n+".src")
Again it is inefficient, here compared to using square-bracket
notation for property access:
document.images['img'+n].src
It is also error prone. There is no syntax check, and if the variable
"n" contains something you didn't expect, then the failure can be
hard to find. If the property is called something that is not an
identifier (typically "foo[]", used by PHP for form controls, or
perhaps "foo1.1"), then the eval method fails completely.

This is what I take as a sign that the author doesn't know the
language very well. Often the reason for using eval like this is
that they don't know about this way to do property access, which
is a fundamental part of the language. Using eval like this is a
crutch that allows them to stagger along, getting something to
run, whereas knowing the language would let them run :)

Then there is the third misuse (which the mentioned calendar program
also sufferend from): throwing in an eval "just for good measure",
even though someone who knows the language can see that it doesn't do
anything. :)

So, eval isn't evil, that's just a good slogan :)

Eval is *very* slow and dangerously error prone!

For *that* reason, it should be avoided in 99.999% of all cases. As
for the remaining two, when you meet them, you'll hopefully know the
language well enough to be able to recognize them.

/L
 
M

Michael Winter

Anytime eval() usage is brought up in this ng it gets jumped on.
Click to expand...

Unless this is purely for the OP's benefit, and I misunderstood, you
haven't grasped my point: I'm not recommending eval (where is an eval call
in my code?), I'm saying that getElementById is not the correct approach.

[snip]

Mike
 
T

Thomas 'PointedEars' Lahn

McKirahan said:
Michael Winter said:
[snip]
1) Use "document.getElementById" not "eval()".
Click to expand...

Why? Neither is the optimum solution (though gEBI is better).

document.forms[0].elements['miles' + n].value ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
gEBI requires a recent browser. The line above doesn't.
Click to expand...
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
http://www.jibbering.com/faq/#FAQ4_40
Click to expand...

You read, but you do not understand.


PointedEars
 

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