Variable Substitution

[Dennis Marks]

In the following function:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document.theMe nu.visibility = theAction;}
else {document.all.t heMenu.style.vi sibility = theAction;}}
}

Will the passed value of theMenu be substituted in the last 2 lines or
will it use "theMenu" as the value?

The following words are in the last line:
document
all
theMenu
style
visibility

Since all are reserved words except for "theMenu" is that term
changable?

Do I have to use the following:
eval("document. all."+theMenu+" .style.visibili ty")

I have no way to test it.

--
Dennis Marks
http://www.dcs-chico.com/~denmarks/
To reply change none to dcsi.
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[Ivo]

"Dennis Marks" asked

In the following function:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document.theMe nu.visibility = theAction;}
else {document.all.t heMenu.style.vi sibility = theAction;}}
}

Will the passed value of theMenu be substituted in the last 2 lines or
will it use "theMenu" as the value?
The latter.
Do I have to use the following:
eval("document. all."+theMenu+" .style.visibili ty")

No. Try document.all[theMenu].style.etc.
with square brackets, no eval and no quotes.
HTH
Ivo

[Lasse Reichstein Nielsen]

Dennis Marks <de******@none. net> writes:

In the following function:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document.theMe nu.visibility = theAction;}
else {document.all.t heMenu.style.vi sibility = theAction;}}
}

Will the passed value of theMenu be substituted in the last 2 lines or
will it use "theMenu" as the value?
It will use the literal text "theMenu", since you are not writing a
variable.

The following words are in the last line:
document
all
theMenu
style
visibility

Since all are reserved words except for "theMenu" is that term
changable?
None of the words are reserved in the Javascript language. The reserved
words are at the end of this page:
<URL:http://www.crockford.c om/javascript/survey.html>
(Hmm, of the six ways a reserved word can't be used, I think the first
should be "As an *unquoted* name in linteral object notation")

The identifiers have the following meaning:

- The variable "document" refers to the variable of that name. This is
usually the global variable, i.e., a property of the global object with
that name. The value of the variable is used.

- The identifier "all" is used as part of a property accessor (due to
the "."), and is not interpreted as a variable. The name of the
identifier is used. The document object of some browsers has a
property called "all", so you find that.

- The identifier "theMenu" is used as part of a property accessor (due
to the "."), and is not interpreted as a variable. The name of the
identifier is used. The object referenced by "document.a ll" may, or
may not, have a property of that name.

etc.
Do I have to use the following:
eval("document. all."+theMenu+" .style.visibili ty")
Never. Never use eval, you don't need it, and the alternatives are
both safer and more efficient.
<URL:http://jibbering.com/faq/#FAQ4_40>

Use:
document.all[theMenu].style.visibili ty
<URL:http://jibbering.com/faq/#FAQ4_39>

In this notation, the part inside the [...] is an *expression*. In
this case it is a expression consisting of a single variable, but
it will be evaluated and its value used, not its name.
I have no way to test it.

No browser at all?

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

[Dennis Marks]

In article <n0**********@h otpop.com>, Lasse Reichstein Nielsen
<lr*@hotpop.com > wrote:

Dennis Marks <de******@none. net> writes:

In the following function:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document.theMe nu.visibility = theAction;}
else {document.all.t heMenu.style.vi sibility = theAction;}}
}

Will the passed value of theMenu be substituted in the last 2 lines or
will it use "theMenu" as the value?

<snip>
Use:
document.all[theMenu].style.visibili ty
<URL:http://jibbering.com/faq/#FAQ4_39>

In this notation, the part inside the [...] is an *expression*. In
this case it is a expression consisting of a single variable, but
it will be evaluated and its value used, not its name.

I have no way to test it.

No browser at all?

In my browsers only the statement immediately after the "if" is run.
The "else" portions are for other browsers. At least that is my
understanding. Please inform me if I am incorrect. I would like to
simplify it if possible.

The revised function is:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document[theMenu].visibility =
theAction;}
else {document[theMenu].style.visibili ty = theAction;}}
}

--
Dennis Marks
http://www.dcs-chico.com/~denmarks/
To reply change none to dcsi.
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[Robert]

In article <12************ *************@n one.net>,
Dennis Marks <de******@none. net> wrote:

In my browsers only the statement immediately after the "if" is run.
The "else" portions are for other browsers. At least that is my
understanding. Please inform me if I am incorrect. I would like to
simplify it if possible.

The revised function is:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document[theMenu].visibility =
theAction;}
else {document[theMenu].style.visibili ty = theAction;}}
}

You could look in a public library for some books on IE with a cd-rom in
them. Look for IE 4.5.

You could comment out the code for newer browsers and let the new IE run
with the old code.

Robert

[Lasse Reichstein Nielsen]

Dennis Marks <de******@none. net> writes:
Dennis Marks <de******@none. net> writes:

In my browsers only the statement immediately after the "if" is run.

Then get some more browsers!

Netscape 2 (JavaScript 1.0):
Netscape 3 (JavaScript 1.1):
Netscape 4.00-4.05 (JavaScript 1.2):
Netscape 4.06-4.80 (JavaScript 1.3):
Netscape 7 (JavaScript 1.4):
<URL:http://wp.netscape.com/download/archive.html>
Mozilla FireFox (same engine as Netscape 7, just more recent version):
<URL:http://www.mozilla.org/products/firefox/>

IE 3 (JScript 1.0):
IE 4 (JScript 3.0):
IE 5.01 (JScript 5.0):
IE 5.5 (JScript 5.5):
<URL:http://www.quirksmode. org/browsers/multipleie.html >

Opera v. 3.62, 5.12, 6.06, 7.11 (soon 7.23):
<URL: http://arc.opera.com/pub/opera/win/ >
Opera 7.5:
<URL: http://www.opera.com/download/ >
(I have a version 4 too, if you want it)

Earlier verions of these browsers didn't support Javascript.

If that's not enough, here is the rest:
<URL:http://browsers.evolt. org/>

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

[Ivo]

"Dennis Marks" wrote

In my browsers only the statement immediately after the "if" is run.
The "else" portions are for other browsers. At least that is my
understanding. Please inform me if I am incorrect. I would like to
simplify it if possible.

The revised function is:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document[theMenu].visibility =
theAction;}
else {document[theMenu].style.visibili ty = theAction;}}
}

There are two brackets too many in this function. The one just before "if
(document.layer s)" and the last one should be removed. Currently the logic
looks like:

if (foo) { x=1; } else { if (bar) x=2; } else { x=3; }

which is not logical. I suspect you meant:

if (foo) { x=1; } else if (bar) { x=2; } else{ x=3; }
If you don't have all the browsers you aim to support, there is little in
scripting for them. Even the best need to test. To test stuff for older
browsers, you can usually turn the "if" around (temporarily) with a ! in the
right place.
HTH
Ivo

[Dennis Marks]

In article <pt**********@h otpop.com>, Lasse Reichstein Nielsen
<lr*@hotpop.com > wrote:

Dennis Marks <de******@none. net> writes:
Dennis Marks <de******@none. net> writes:

In my browsers only the statement immediately after the "if" is run.

Then get some more browsers!

Netscape 2 (JavaScript 1.0):
Netscape 3 (JavaScript 1.1):
Netscape 4.00-4.05 (JavaScript 1.2):
Netscape 4.06-4.80 (JavaScript 1.3):
Netscape 7 (JavaScript 1.4):
<URL:http://wp.netscape.com/download/archive.html>
Mozilla FireFox (same engine as Netscape 7, just more recent version):
<URL:http://www.mozilla.org/products/firefox/>

IE 3 (JScript 1.0):
IE 4 (JScript 3.0):
IE 5.01 (JScript 5.0):
IE 5.5 (JScript 5.5):
<URL:http://www.quirksmode. org/browsers/multipleie.html >

Opera v. 3.62, 5.12, 6.06, 7.11 (soon 7.23):
<URL: http://arc.opera.com/pub/opera/win/ >
Opera 7.5:
<URL: http://www.opera.com/download/ >
(I have a version 4 too, if you want it)

Earlier verions of these browsers didn't support Javascript.

If that's not enough, here is the rest:
<URL:http://browsers.evolt. org/>

/L

Don't assume I am on a PC. I am on a Mac using system 9. I am not able
to use any of the latest browsers. They require system X and I don't
wish to invest in an upgrade since I might soon switch to a PC. That is
why I asked if the function was correct.

--
Dennis Marks
http://www.dcs-chico.com/~denmarks/
To reply change none to dcsi.
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[Dennis Marks]

In article <40************ ***********@new s.wanadoo.nl>, Ivo
<[e-mail] > wrote:

"Dennis Marks" wrote

In my browsers only the statement immediately after the "if" is run.
The "else" portions are for other browsers. At least that is my
understanding. Please inform me if I am incorrect. I would like to
simplify it if possible.

The revised function is:

function showMenu(theMen u, theAction) {
if (document.getEl ementById)
{document.getEl ementById(theMe nu).style.visib ility = theAction;}
else {if (document.layer s) {document[theMenu].visibility =
theAction;}
else {document[theMenu].style.visibili ty = theAction;}}
}

There are two brackets too many in this function. The one just before "if
(document.layer s)" and the last one should be removed. Currently the logic
looks like:

if (foo) { x=1; } else { if (bar) x=2; } else { x=3; }

which is not logical. I suspect you meant:

if (foo) { x=1; } else if (bar) { x=2; } else{ x=3; }
If you don't have all the browsers you aim to support, there is little in
scripting for them. Even the best need to test. To test stuff for older
browsers, you can usually turn the "if" around (temporarily) with a ! in the
right place.
HTH
Ivo

Thank you for your help. I am just creating a general division
show/hide function based on information that I have found in this
group.
I assume that the 3 methods used to show/hide are used by different
browsers. My browsers use getElementById.
The two forms of document{theMen u] do not work on my browsers. My
question is are they valid and are they necessary? I'll remove it if it
is only necessary for a few old browsers.

--
Dennis Marks
http://www.dcs-chico.com/~denmarks/
To reply change none to dcsi.
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