Validating a drop down (select) type, form element

[Terry Murray]

Hi everybody:
I am trying to write a generic function, isValidMonth, that can used on 2
form elements, smonth and emonth. I would like the function to test whether
the user has selected a month or not.
If anyone can help me I would really appreciate it. What I have done
follows.

My form has:

<SELECT name=smonth>
<OPTION value=0>-Month-
<OPTION value=1>Jan
<OPTION value=2>Feb
<OPTION value=3>Mar
...
<OPTION value=12>Dec
</SELECT>

<SELECT name=emonth>
<OPTION value=0>-Month-
<OPTION value=1>Jan
<OPTION value=2>Feb
<OPTION value=3>Mar
...
<OPTION value=12>Dec
</SELECT>
..
My JavaScript contains:

function isValidMonth(month) {
if (month[month.selectedIndex].value == 0
return false
return true
}
function submitIt(form) {
if (!isValidmonth(smonth))
alert("You have not selected a start month")
return true
}

Thank you

Terry

[kaeli]

In article <Q6*******************@news04.bloor.is.net.cable.r ogers.com>,
tg******@rogers.com enlightened us with...

<SELECT name=smonth>
quote attributes.
sname="month"
<OPTION value=0>-Month- value="0"
.
My JavaScript contains:

function isValidMonth(month) {
if (month[month.selectedIndex].value == 0
return false
return true
}

Better programming practice (only one exit) and a correction

function isValidMonth(month) {
b = true;
if (month.options[month.selectedIndex].value == 0
b = false
return b
}

function submitIt(form) {
if (!isValidmonth(smonth))
alert("You have not selected a start month")
return true
}

return value needed; keyword changed; correction to call

function submitIt(frm) {
b = true;
if (isValidmonth(frm.smonth))
{
alert("You have not selected a start month");
b = false;
}
return b
}

handler called in onSubmit of form, not onClick of submit

<form name="f1" action="whatever" method="post" onSubmit="return
submitIt(this)">

--
--
~kaeli~
A little rudeness and disrespect can elevate a meaningless
interaction to a battle of wills and add drama to an
otherwise dull day.
http://www.ipwebdesign.net/wildAtHeart
http://www.ipwebdesign.net/kaelisSpace

[Lasse Reichstein Nielsen]

kaeli <ti******@NOSPAM.comcast.net> writes:

Better programming practice (only one exit) and a correction
I'm not sure I agree with that practice in all cases.
function isValidMonth(month) {
b = true;
if (month.options[month.selectedIndex].value == 0
Missing ")". I recommend { ... } around all if branches, even if they
are only a single statement. It makes it easier to extend them later.

From the original poster's description, I would just test:
month.selectedIndex == 0
since his invalid option was the first one.
b = false
return b
}

.... but when it comes to returning booleans with if-statements,
I always want to do it shorter:

function isValidMonth(month) {
return month.selectedIndex != 0;
}

Otherwise, I agree.
/L
--
Lasse Reichstein Nielsen - lr*@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleDOM.html>
'Faith without judgement merely degrades the spirit divine.'

[Terry Murray]

Thanks Kaeli. I think a correction is needed for the code that you provided
me with.
if (!isValidmonth(frm.smonth)) should replace if
(isValidmonth(frm.smonth)) inside of function submitIt(frm).

Terry

"kaeli" <ti******@NOSPAM.comcast.net> wrote in message
news:MP************************@nntp.lucent.com...

In article <Q6*******************@news04.bloor.is.net.cable.r ogers.com>,
tg******@rogers.com enlightened us with...

<SELECT name=smonth>

quote attributes.
sname="month"

<OPTION value=0>-Month-

value="0"

.
My JavaScript contains:

function isValidMonth(month) {
if (month[month.selectedIndex].value == 0
return false
return true
}

Better programming practice (only one exit) and a correction

function isValidMonth(month) {
b = true;
if (month.options[month.selectedIndex].value == 0
b = false
return b
}

function submitIt(form) {
if (!isValidmonth(smonth))
alert("You have not selected a start month")
return true
}

return value needed; keyword changed; correction to call

function submitIt(frm) {
b = true;
if (isValidmonth(frm.smonth))
{
alert("You have not selected a start month");
b = false;
}
return b
}

handler called in onSubmit of form, not onClick of submit

<form name="f1" action="whatever" method="post" onSubmit="return
submitIt(this)">

--
--
~kaeli~
A little rudeness and disrespect can elevate a meaningless
interaction to a battle of wills and add drama to an
otherwise dull day.
http://www.ipwebdesign.net/wildAtHeart
http://www.ipwebdesign.net/kaelisSpace