Can anyone tell me why the selectedLength function is failing in the code below?
It can be played with here: http://jsbin.com/oluyu6/3/edit
Thanks.
Svend -
<!DOCTYPE html>
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<html>
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<head>
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<script class="jsbin" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
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<meta charset=utf-8 />
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<title>JS Bin</title>
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<style type="text/css">
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<!--
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option.emphasised {
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background-color: white;
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color: blue;
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font-style: oblique;
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}
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-->
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</style>
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<script>
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function selectedLength(box)
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{
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selected = [];
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for(var i=0; i< box.options.length;i++)
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{
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if(box.options[i].selected) selected.push( box.options[i].value);
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}
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return selected.length;
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}
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function toggleArrowBySelectedVal(option_array, list, arrow)
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{
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if ( (selectedLength(list)==1) &&
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(option_array.find(Number(list.value)))) arrow.disabled=false;
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else arrow.disabled=true;
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}
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window.onload = (function(){
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$("#first").change(function() {
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toggleArrowBySelectedVal([8,15],$("#first"),$("#expandPlus1PDC"));});
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})
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</script>
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<!--[if IE]>
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<script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script>
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<![endif]-->
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<style>
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article, aside, figure, footer, header, hgroup,
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menu, nav, section { display: block; }
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</style>
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</head>
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<body>
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<p id="hello">Hello World</p>
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<SELECT NAME="first" SIZE=13 multiple id="first" selectedIndex=-1>
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<option value="1" class="">A</option>
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<option value="2" class="">B</option>
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<option value="8" class="emphasized">C</option>
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<option value="15" class="emphasized">D</option>
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<option value="10" class="">E</option>
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</select>
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<input name="expandPlus1PDC" type="button" disabled id="expandPlus1PDC" title="Expand list" value=">>">
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</body>
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</html>
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$("#first option:selected").length, why working around something jQuery has a syntax for.
5  2017 
because $("#first") is a jQuery object and not a <select> object.
Thanks for the response. I'm (probably obviously) a newbie to jQuery. What syntax should I be using instead?
I find it weird, because a bunch of other functions with form objects passed this way seem to work fine. Is there a different syntax because the object involved is bound to the function? Were it normal JS, I'd just use "this", but didn't work.
Thanks.
$("#first option:selected").length, why working around something jQuery has a syntax for.
Well, the thing is that I'm trying to make these functions refactor-able. If I use $("#first option:selected").length inside the selectedLength() function, it obviously becomes a one-off function.
Oh, I see what you mean. I solved it with this:
var numselected=$("#"+list_id+" option:selected").length;
which removed that 2nd function entirely.
Thanks.
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