JavaScript Forum

**LayneMitch** · 12-16-2008, 11:24 AM

Hello.

Can anyone tell me why in this simple code my variable "the_values" is showing undefined in Firebug? or better yet..why it's not doing anything...

Code:

<html><head><title>Whatever</title>
<script type="text/javascript">

function attachHandlers(){
var the_button = document.getElementById("the_click");
the_button.onclick=showPicks();
}

function showPicks(){
var the_values = document.getElementsByName("the_numbers").value;

var my_selections = new Array();

for (var i=0; i<the_values.length; i++){
my_selections= the_values[i];
}

alert(my_selections);

}
</script></head>

<body onload="attachHandlers()">
<form>
<input type="textbox" name="the_numbers" size="1" value="1">
<input type="textbox" name="the_numbers" size="1" value="2">
<input type="textbox" name="the_numbers" size="1" value="3">
<input type="textbox" name="the_numbers" size="1" value="4"><br>
<input type="button" value="checknumbers" size="1" id="the_click">
</form>
</body>
</html>

**wayfarer07** · 12-16-2008, 12:06 PM

This line is meaningless:

Code:

var the_values = document.getElementsByName("the_numbers").value;

Since you can't access the value attribute this way. getElementsByName creates an array of objects with "the_numbers" as a name attribute. Each of these objects will have attributes such as value attached to them, but to access them, you must loop over the array. So the above line becomes this:

Code:

var the_values = document.getElementsByName("the_numbers");

For another thing, the line my_selections=the_values[i] is probably not doing what you expect it to, since you defined my_selections as an array right above there. To add an element to the next item in an array, use the array's push method:

Code:

my_selections.push(the_values[i].value);

**LayneMitch** · 12-17-2008, 10:17 AM

Quote:

Originally Posted by wayfarer07

This line is meaningless:

Code:

var the_values = document.getElementsByName("the_numbers").value;

Since you can't access the value attribute this way. getElementsByName creates an array of objects with "the_numbers" as a name attribute. Each of these objects will have attributes such as value attached to them, but to access them, you must loop over the array. So the above line becomes this:

Code:

var the_values = document.getElementsByName("the_numbers");

For another thing, the line my_selections=the_values[i] is probably not doing what you expect it to, since you defined my_selections as an array right above there. To add an element to the next item in an array, use the array's push method:

Code:

my_selections.push(the_values[i].value);

Got it...I wasn't thinking about that array and how I would have to loop through it first...also I completely forgot about the push() method. Thanks.