[SOLVED] Syntax problem -- object has no properties

[dsmithhfx]

I just realized I posted this here instead of the javascript folder... can a moderator move it there, by any chance? thanks!

Hi,

I've got a script that works, but is returning an error in Firebug:

HTML: Select all

var thirdpngs = document.getElementsByName('last');

function showit(){
    for (iName in thirdpngs){
    thirdpngs[iName].style.display = 'inline';    
    }   
}

function hideit(){
    for (iName in thirdpngs){
    thirdpngs[iName].style.display = 'none';    
    }   
}

The error is "thirdpngs[iName].style has no properties"

I'm puzzled because:

HTML: Select all

var thirdpngs = document.getElementsByName('last');

function showit(){
    thirdpngs[0].style.display = 'inline'; 
    thirdpngs[1].style.display = 'inline'; 
    thirdpngs[2].style.display = 'inline'; 
}

function hideit(){
    thirdpngs[0].style.display = 'none'; 
    thirdpngs[1].style.display = 'none'; 
    thirdpngs[2].style.display = 'none'; 
}

doesn't return any errors.


Fixed:

HTML: Select all

var thirdpngs = document.getElementsByName('last');
function showit(){
    for (var i = 0; i <= 2; i++) {
        thirdpngs[i].style.display = 'inline';
    }
}

function hideit(){
    for (var i = 0; i <= 2; i++) {
        thirdpngs[i].style.display = 'none';
    }
}

-------------
[at least in Firefox; script doesn't work in IE7...)

[spinal007]

"Object has no properties" basically happened because you were trying to use an element that didn't exist (null).

To avoid the problem, this line:
for (var i = 0; i <= 2; i++) {

should actually be written like this:
for (var i = 0; i < thirdpngs.length; i++) {

...so it will work when you have 1, 2, 3 or 7 million items in the array.

[dsmithhfx]

see "Fixed" ^^^. The error is/was no more...

[spinal007]

read my post and you will see that, although you have it working, the proper way to code it will avoid this problem in the future. it's good practice not to hard code the length of arrays - the whole purpose is for them to be dynamic...

[dsmithhfx]

[alexgeek]

Moved and Solved.

[dsmithhfx]

Thanks Alex.