Null in Javascript code

Hello,

Below is my code:

In the above code, when the field.value.length is 0 , the loop gets executed,
how come helpText is not null ?

Also
For the above loop, if I enter message in the field, the rest of the fields go off the screen.
The solution to this is that I need to change the above loop condition to
Why do I need to change this from != to == ?

Please advise.

validateNonEmpty(this,document.getElementById('message_help')

this means helptext = document.getElementById('message_help');
and as your form has
<span id="message_help" />

helpText would never be null..

in fact you could rewrite

as

Hey Joy,

So I assume that as helpText is referring to something (element "message_help") so it can't be null.

What I don't understand is that why I need to write "==" instead of "!=".
Actually the book I'm using does show "!=" but it doesn't work.

Also, as helpText is not null and so is my message field, then how come helpText becomes null or why is this condition getting executed ?

Joy,

validateNonEmpty(this,document.getElementById('message_help')

this means helptext = document.getElementById('message_help');
and as your form has
<span id="message_help" />

helpText would never be null..

Then why

is getting executed ?

I'm not getting that alert ..please check
also i strongly recommend you to put the missing brackets else its very confusing

if()
alert(1);
if()
alert(2);
alert(3);
alert(4)

to be honest i don't know which all alerts will popup