Javascript Error (Line: 1 Char: 1 Error: Object Expected Code: 0)

[whatelyb]

I am having trouble related to the attached coding.

I am trying to make the object "flight1pic" change depending on what is selected in the drop down menus "airline1" and "aircraft1".

My problem is when changing "airline1" it all works fine, but when changing "aircraft1" i get the error:

Line: 1
Char: 1
Error: Object Expected
Code: 0

function flightpicFunction(){
    if(document.getElementById('airline1').value == "Qantaslink" && document.getElementById('aircraft1').value == "Boeing 717"){ document.getElementById('flight1pic').innerHTML = "<img src=../images/aircraft/QF_B717.jpg>"; }
    if(document.getElementById('airline1').value == "Skywest" && document.getElementById('aircraft1').value == "Fokker 100"){ document.getElementById('flight1pic').innerHTML = "<img src=../images/aircraft/XR_F100.jpg>"; }
}
 

Can anyone tell me what i might be doing wrong?

<select size="1" onChange="flightpicFunction();" name="aircraft1" tabindex="3">
  <option value="BAe 146">BAe 146</option>
  <option value="Boeing 717">Boeing 717</option>
  <option value="Boeing 737">Boeing 737</option>
  <option value="Dash 8">Dash 8</option>
  <option value="Embraer 120">Embraer 120</option>
  <option value="Embraer 145">Embraer 145</option>
  <option value="Embraer 170">Embraer 170</option>
  <option value="Embraer 190">Embraer 190</option>
  <option value="Fokker 100">Fokker 100</option>
  <option value="Fokker 50">Fokker 50</option>
  <option value="Other">Other</option>
</select>
 

[Frinavale]

I've moved your question from the Java forum into the JavaScript forum where you will find more help with your JavaScript question.


Select HTML elements consist of a bunch of options.
It doesn't make sense to set a select HTML element's "value" property because it doesn't have a value....it has a bunch of options.

-Frinny

[whatelyb]

@Frinavale
Sorry, can you explain it to me in lamens (easy) terms? I'm good with PHP but I really haven't the slightest clue with Javascript.

[whatelyb]

I have tried replacing the code:

document.getElementById('aircraft1').value
 

with this code:

document.navform.aircraft1.options[document.navform.aircraft1.selectedIndex].value
 

And I still get the same error. :(

[whatelyb]

Sorry to mess you around. The problem turned out to be my PHP coding.

The PHP coding I had set up changed which javascript function the dropdown menu called up, to one that didn't exist.

All works fine now. Thanks.

[thesmithman]

You are on the right track with selectedIndex.

try something like:

var dropdown = document.forms[0].aircraft1;
var selection = dropdown[dropdown.selectedIndex].value;
 

Here's a reference for more information:
http://www.w3schools.com/jsref/prop_...ectedindex.asp

And by the way, I highly recommend doing your JavaScript debugging in a different browser. Those Internet Explorer error messages just aren't that helpful. There is a handy plugin for Firefox called Firebug; and there are developer tools built in to the Chrome browser.

Happy coding!

[thesmithman]

I see you got it sorted out before I hit the "post reply" button! Glad to hear it.

[whatelyb]

Yeah thanx anyway "thesmithman" and also "Frinavale". I suppose the best diagnosis is a good night sleep. Was trying to figure it all out at 2am in the morning (before I relised what time it was.)

[Frinavale]

Internet Explorer 8 comes with a debugger (hit F12).
If you like FireFox then download a plugin called FireBug.

-Frinny

[Dormilich]

two things from my side.

your <select> does not have an ID, so trying to access it with getElementById() will only work in IE (given the name is unique, too).

second, a <select> indeed has a value property, which you can read and write.