[Proto-Scripty] Re: Building a string for an array reference
T.J.,
Thanks so much for the reply. I completely blanked on that way of
referencing it, and appreciate you filling me in on it. That worked
perfectly for me.
On Apr 11, 12:16 am, T.J. Crowder t...@crowdersoftware.com wrote:
Hi,
You can reference a property of an object using a string key and
square brackets, so this:
var itemsToShow = myOptions. + sel;
should be:
var itemsToShow = myOptions[sel];
...assuming that `sel` contains a string like myOptions_group1, as
it appears to from the if/else structure you said works.
This is one of the more powerful features of JavaScript syntax, this
ability to reference a property by symbol:
x = myOptions.myOptions_group1;
...or by string, either a string literal:
x = myOptions[myOptions_group1];
...or a string in a variable:
s = myOptions_group1;
x = myOptions[s];
...since of course those are the same thing as far as the [] operator
is concerned.
HTH,
--
T.J. Crowder
Independent Software Consultant
tj / crowder software / comwww.crowdersoftware.com
On Apr 9, 2:56 am, thegdog theg...@gmail.com wrote:
So here's what I am trying to do.
I have a form with two select fields: issue and subissue. The
second (subissue) is hidden by default. When the user selects one of
the items in the first (issue), I want to populate the second with
only certain options.
So I have all the options in the subissue select and it is set to
display: none. When the user selects an option in the issue select,
I pass the value to the processIssue function, which first hides all
the options in the subissue select. Then it builds out the name of
the array reference. ANd in theory, uses that to show certain options
(based on their ids in the arraty), and then unhide the select.
The problem is that when it hits the if block, itemsToShow is a
string, not the array reference.
Here is some of the relevant code as I have it:
script type=text/javascript
var myOptions = {
myOptions_group1: [ group1_1, group1_2, group1_3, group1_4
],
myOptions_group2: [ group2_1, group2_2 ],
myOptions_group3: [ group3_1, group3_2 ]
}
function processIssue(sel) {
$$(#subissueoption).invoke(hide);
var itemsToShow = myOptions. + sel;
if (itemsToShow) {
for (var i=0, l=itemsToShow.length; il; i++) {
$(itemsToShow[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
}
/script
form
select name=issue id=issue onchange=processIssue(this.value)
option value=myOptions_group1Group 1/option
option value=myOptions_group2Group 2/option
option value=myOptions_group3Group 3/option
option value=myOptions_group4Group 4/option
/select
select name=subissue id=subissue
option id=group1_11_1/option
option id=group1_21_2/option
option id=group1_31_3/option
option id=group1_41_4/option
option id=group2_12_1/option
option id=group2_22_2/option
option id=group3_13_1/option
option id=group3_23_2/option
/select
/form
If I change the processIssue function to this, it works great:
function processIssue(sel) {
$$(#subissueoption).invoke(hide);
if (sel == 'myOptions_group1') {
for (var i=0, l=myOptions.myOptions_group1.length; il;
i++) {
$(myOptions.myOptions_group1[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
else if (sel == 'myOptions_group2') {
for (var i=0, l=myOptions.myOptions_group2.length; il;
i++) {
$(myOptions.myOptions_group2[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
else if (sel == 'myOptions_group3') {
for (var i=0, l=myOptions.myOptions_group3.length; il;
i++) {
$(myOptions.myOptions_group3[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
else {
$(issueRefine).style.display = 'none';
}
}
I was hoping to avoid this however, as the list is going to be pretty
long and I wanted to reduce the amount of code.
Can anyone suggest a good way to do this? I will admit that I am not
the most proficient JS developer on the planet, but I usually have a
good understanding of things. Just not sure how I can build the
reference to the array object.
Would appreciate any assistance you could provide.
--
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[Proto-Scripty] Re: Building a string for an array reference
Hi,
You can reference a property of an object using a string key and
square brackets, so this:
var itemsToShow = myOptions. + sel;
should be:
var itemsToShow = myOptions[sel];
...assuming that `sel` contains a string like myOptions_group1, as
it appears to from the if/else structure you said works.
This is one of the more powerful features of JavaScript syntax, this
ability to reference a property by symbol:
x = myOptions.myOptions_group1;
...or by string, either a string literal:
x = myOptions[myOptions_group1];
...or a string in a variable:
s = myOptions_group1;
x = myOptions[s];
...since of course those are the same thing as far as the [] operator
is concerned.
HTH,
--
T.J. Crowder
Independent Software Consultant
tj / crowder software / com
www.crowdersoftware.com
On Apr 9, 2:56 am, thegdog theg...@gmail.com wrote:
So here's what I am trying to do.
I have a form with two select fields: issue and subissue. The
second (subissue) is hidden by default. When the user selects one of
the items in the first (issue), I want to populate the second with
only certain options.
So I have all the options in the subissue select and it is set to
display: none. When the user selects an option in the issue select,
I pass the value to the processIssue function, which first hides all
the options in the subissue select. Then it builds out the name of
the array reference. ANd in theory, uses that to show certain options
(based on their ids in the arraty), and then unhide the select.
The problem is that when it hits the if block, itemsToShow is a
string, not the array reference.
Here is some of the relevant code as I have it:
script type=text/javascript
var myOptions = {
myOptions_group1: [ group1_1, group1_2, group1_3, group1_4 ],
myOptions_group2: [ group2_1, group2_2 ],
myOptions_group3: [ group3_1, group3_2 ]
}
function processIssue(sel) {
$$(#subissueoption).invoke(hide);
var itemsToShow = myOptions. + sel;
if (itemsToShow) {
for (var i=0, l=itemsToShow.length; il; i++) {
$(itemsToShow[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
}
/script
form
select name=issue id=issue onchange=processIssue(this.value)
option value=myOptions_group1Group 1/option
option value=myOptions_group2Group 2/option
option value=myOptions_group3Group 3/option
option value=myOptions_group4Group 4/option
/select
select name=subissue id=subissue
option id=group1_11_1/option
option id=group1_21_2/option
option id=group1_31_3/option
option id=group1_41_4/option
option id=group2_12_1/option
option id=group2_22_2/option
option id=group3_13_1/option
option id=group3_23_2/option
/select
/form
If I change the processIssue function to this, it works great:
function processIssue(sel) {
$$(#subissueoption).invoke(hide);
if (sel == 'myOptions_group1') {
for (var i=0, l=myOptions.myOptions_group1.length; il; i++) {
$(myOptions.myOptions_group1[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
else if (sel == 'myOptions_group2') {
for (var i=0, l=myOptions.myOptions_group2.length; il; i++) {
$(myOptions.myOptions_group2[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
else if (sel == 'myOptions_group3') {
for (var i=0, l=myOptions.myOptions_group3.length; il; i++) {
$(myOptions.myOptions_group3[i]).style.display = '';
}
$(issueRefine).style.display = '';
}
else {
$(issueRefine).style.display = 'none';
}
}
I was hoping to avoid this however, as the list is going to be pretty
long and I wanted to reduce the amount of code.
Can anyone suggest a good way to do this? I will admit that I am not
the most proficient JS developer on the planet, but I usually have a
good understanding of things. Just not sure how I can build the
reference to the array object.
Would appreciate any assistance you could provide.
--
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