[SOLVED] Simple variable question

[rhyspaterson]

Hey lads,

 

Writing a whole load of PHP code and realized i needed to use a tiny bit of JavaScript (which i know nothing about). I have a line that looks like this:

 

document.clientCategoriesForm.adultContent.options.length=0;

 

This is inside a FOR loop which uses 'i' as the loop variable, and i wanted to replace .adultContent. with .i. above, but now sure how to do it. In PHP it would be;

 

document.clientCategoriesForm.$i.options.length=0;

 

What is the JS equivalent? Cheers!

[arianhojat]

Not sure what you want....

 

Set everything inside of clientCategoriesForm to 0?

document.clientCategoriesForm.options.length=0;

or mess with options themselves

document.clientCategoriesForm.adultContent.options

 

[xenophobia]

Just replace with 'i' without the dollar sign:

document.clientCategoriesForm.$i.options.length=0;

[rhyspaterson]

Hey guys,

 

Figured i would give you a bit more info to help me figure this out, heh. Basically i have 32 select menus, each with two states, allow and block. Using PHP i am connecting to a PostgreSQL database and defining the initial states of these select menus when the pages loads (based on the data in the database). This is all fine. What i would like to do now, and can't do with PHP (at least i think i can't), is have a button that will change all the select menus to allow or block. Based on my research i came up with this code:

 

<select name="0"> // names will go from 0 to 32
<?php
if ($line[0][1] == 0) {
    echo '<option value="1">Block</option>';
    echo '<option value="0" selected="selected">Allow</option>';
} else {
    echo '<option value="1" selected="selected">Block</option>';
    echo '<option value="0">Allow</option>';
}
?>
</select>

 

function changeStateAllow()
{
for (i=0; i<32; i++){
                document.clientCategoriesForm.i.options.length=0;
	document.clientCategoriesForm.i.options[0]=new Option("Allow", "0", true, false);
	document.clientCategoriesForm.i.options[1]=new Option("Block", "1", false, false);
}
}
</script>

...

<input type="button" value="Allow All" onclick="changeStateAllow()" >

 

What i wanted to happen is, with my select menus named 0,1, 2, 3, 4 .. all the way to 32, run this loop when a button is clicked, and change each state to allow. Now i know i probably don't need to delete all the options and recreate them, but i just wanted to get the damn thing to work first before improving the coding, haha.

 

Unfortunately this code doesn't work, and i am a bit confused as to how to go about it now. Could anyone point me in the right direction?

 

Thanks heaps guys

[mainewoods]

like this:

for (i=0; i<32; i++){
                document.clientCategoriesForm[i].options.length=0;

[rhyspaterson]

Thanks for the reply!

 

Did some testing (as it did not work), and think i may have figured out why. When i run the code:

 

document.clientCategoriesForm.x.selectedIndex = 1;

 

(where x is the name of the select menu), when x is a number it does not work, but if it is a word, the function does. Any reason for that? (obviously i am changing the select names to words or numbers for the testing heh)

 

I.e

 

This works:

<script type="text/javascript"> 
function changeStateAllow(){
	document.clientCategoriesForm.adultContent.selectedIndex = 1;
	document.clientCategoriesForm.wwwEmailSites.selectedIndex = 1;
	document.clientCategoriesForm.news.selectedIndex = 1;
	document.clientCategoriesForm.violenceUndesirable.selectedIndex = 1;
}
</script>

This does not:

<script type="text/javascript"> 
function changeStateAllow(){
	document.clientCategoriesForm.1.selectedIndex = 1;
	document.clientCategoriesForm.17.selectedIndex = 1;
	document.clientCategoriesForm.2.selectedIndex = 1;
	document.clientCategoriesForm.18.selectedIndex = 1;
}
</script>

 

Cheers

[mainewoods]

the way to use variables in dom access is the way I showed using the brackets. But I believe the .length property in select items is read only:

http://www.w3schools.com/htmldom/dom_obj_select.asp

 

 

[rhyspaterson]

Ah sorry, i figured it out haha. I had a . in the wrong place.

 

document.clientCategoriesForm.[i].selectedIndex = 1;

 

should have been

 

document.clientCategoriesForm[i].selectedIndex = 1;

 

Thanks so much for your help

 

[mainewoods]

the rule with the []s is like this:

-do not use . before the brackets

-between the brackets you can put a number, a string, or a js var

 

document.formname['literalfieldname'].propertyname = ' ';
document.formname[2].propertyname = ' ';
document.formname[jsvariable].propertyname = ' ';

 

-if I wanted to use js vars for the formname as well as the field name:

document[myformname][myfieldname].propertyname = ' ';

 

Use the []'s to use js vars to access the dom, don't use eval()