Populate HTML listbox using javascript function on page load

Question

I have a HTML Listbox and I need to add values to it on the page load. I have tried to call a JS function on page load event on both <body> tag and <select> tag but it does not execute the the function.

<body onload='popListbox(<%=session.getAttribute("objNames")%>)'>

<select id="lstObjects" onload='popListbox(<%=session.getAttribute("objNames")%>)'>

If I try onclick it executes fine but not in onload event. Can someone help me with this.?

UPDATE: my JS function

function popListbox(objList){

var select = document.getElementById("lstObjects");
var objects = objList;
var objects_array = [];
for(var i in objects) {
    if(objects.hasOwnProperty(i) && !isNaN(+i)) {
        objects_array[+i] = objects[i];
    }
}
for(var i = 0; i < objects_array.length; i++) {
    var opt = objects_array[i];
    var el = document.createElement("option");
    el.textContent = opt;
    el.value = opt;
    select.appendChild(el);
}

}

score 0 · Accepted Answer · answered Mar 17 '14 at 08:28

0

try document.ready

$( document ).ready(function() {

//your code here

});

answered Mar 17 '14 at 08:28

Amarnath R Shenoy

5,121
8
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If I use this method how can I pass the parameter I'm passing in my popListbox() method.? – SajithRu Mar 17 '14 at 08:59
var objNames = '<%= Session["objNames"] %>' – Amarnath R Shenoy Mar 17 '14 at 09:06
u can use that variable as your parameter – Amarnath R Shenoy Mar 17 '14 at 09:06
there are alot of ways which will help you to access values from your session using javascript and jquery – Amarnath R Shenoy Mar 17 '14 at 09:07
it takes all inside single quotes as string value. is there any other way.? :/ – SajithRu Mar 17 '14 at 09:13
http://stackoverflow.com/questions/15519454/how-can-i-access-session-variables-and-set-them-in-javascript – Amarnath R Shenoy Mar 17 '14 at 09:18
Yes it works when I'm writing the JS function in same html page. but I'm using seperate JS file to write JS functions so single quating and accessing sessions variables does not work any more. thats why I had to use a parameter to pass values to JS function in the 1st place. But when I do that I cant use $document.ready(); method. – SajithRu Mar 17 '14 at 09:23
Finally I decide to use JS in same HTML page. thank you for the help. :) – SajithRu Mar 17 '14 at 09:42

aelgoa · Answer 2 · 2014-03-17T08:34:43.913

-1

What's the JS function? I suspect, because only the body tag has an onload handler, perhaps your js function is not aware of the element context when it is triggered from document root.

function popListbox(objList){
var select = document.getElementById('lstObjects');
for(i=0,ic=objList.length;i<ic;++i) {
    var el=document.createElement('option');
    el.textContent=objList[i];
    el.value=objList[i];
    select.appendChild(el);
}
}

I don't know why it doesn't work but I rewrote it because it's the same result

edited Mar 17 '14 at 08:34

answered Mar 17 '14 at 08:22

aelgoa

1,193
1
8
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I have added my JS function. please look into it. – SajithRu Mar 17 '14 at 08:26

Populate HTML listbox using javascript function on page load

2 Answers2