Rails - Sep 2010 - Calling a Javascript method from a view

I have a "coordinate.js" javascript in public/javascripts and in
app/views/dicoms, I have a "show.html.erb".

For example, if I want to call the getWidth function from the .js file
in the view what should I do? I remember it working for me as I get a
message box giving me the alert but don''t know what went wrong.

For example, I have this functionin the .js file

function getWidth() {
  var image = document.getElementById("dicom_image");
  imageWidth = image.width;
  return imageWidth;
  alert("Image Width is " + image.width);
}

And, here is my "show.html.erb" file:

<%= javascript_include_tag "coordinate" %>
<canvas id="draw" >
</canvas>
<p id="notice"><%= notice %></p>
<p>
<b> Name </b>
<%= @dicom.name %>
</p>
<p>
<b> Image </b>
</p>
<div id="image_element" style="display: none;">
<p>
<%= image_tag @dicom.photo.url , :id => ''dicom_image''
%>
</p>
</div>
<%= update_page_tag do |page|
page << "getWidth();"
end
%>
<%= update_page_tag do |page|
page << "drawImg();"
end
%>
<%= update_page_tag do |page|
page << "drawLine();"
end
%>
<%= link_to ''Edit'', edit_dicom_path(@dicom) %>
<%= link_to ''Back'', dicoms_path %>

Please let me know what you think.

Thanks.
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I figured the issue out. I wanted an alert to show up, and had this 
statement BEFORE the alert:

return imageWidth;

So, I had to remove it to see the alert, since it seems that the block 
will exit after the return statement.
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When I try to call the getHeight() and getWidth() functions I get two 
message box telling:

RJS error:
TypeError: image is null

And,

getWidth();

I get that when I do the following in "show.html.erb":

<%= javascript_include_tag "coordinate" %>
<canvas id="draw" height = "<%= update_page_tag do |page|
page << "getHeight();"
end
%>"

width = "<%= update_page_tag do |page|
page << "getWidth();"
end
%>"
>
</canvas>

Provided that, in "coordinate.js", the methods are as follows:

function getWidth() {
  var image = document.getElementById("dicom_image");
  imageWidth = image.width;
  return imageWidth;
}

function getHeight(){
  var image = document.getElementById("dicom_image");
  imageHeight = image.height;
  return imageHeight;
}

What do you think?

Thanks.



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are you using any library?

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radhames brito wrote:
> are you using any library?
I''m using Paperclip to upload an image in my model.
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looks like you are not using any javascript library but are calling a
prototype method or something

 var img = document.getElementById("dicom_image");

var width = img.clientWidth;
var height = img.clientHeight;



On Sun, Sep 19, 2010 at 8:15 AM, Abder-Rahman Ali
<lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org>wrote:
> radhames brito wrote:
> > are you using any library?
>
> I''m using Paperclip to upload an image in my model.
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radhames brito wrote:
> looks like you are not using any javascript library but are calling a
> prototype method or something
> 
>  var img = document.getElementById("dicom_image");
> 
> var width = img.clientWidth;
> var height = img.clientHeight;
So, what do you think should I do to solve the issue?
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If you are learning and want to learn how to do everything nice and
efficiently learn how to use a javascript library, if you are in a hurry
and dont have time to learn keep doing it the way you have. The code i gave
you is for when you are not using any library.

with jquery it would have been as easy as this


$("#dicom_image").width();
$("#dicom_image").height();

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radhames brito wrote:
> If you are learning and want to learn how to do everything nice and
> efficiently learn how to use a javascript library, if you are in a hurry
> and dont have time to learn keep doing it the way you have. The code i 
> gave
> you is for when you are not using any library.
> 
> with jquery it would have been as easy as this
> 
> 
> $("#dicom_image").width();
> $("#dicom_image").height();
At least for the way I''m following right now. Why am I not getting the 
value of the width and height returned in my view?

In other words: How can I call the getHeight() and getWidth() Javascript 
functions in my view here?

<canvas id="draw" height="?????" width="?????"
>
</canvas>

Thanks.


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because without library is

var width =
document.getElementById(''dicom_image'').clientWidth;


or

var image =  document.getElementById(''dicom_image'');

var width = image.clientWidth;


but you are calling

image.width;



On Sun, Sep 19, 2010 at 9:30 AM, Abder-Rahman Ali
<lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org>wrote:
> radhames brito wrote:
> > If you are learning and want to learn how to do everything nice and
> > efficiently learn how to use a javascript library, if you are in a
hurry
> > and dont have time to learn keep doing it the way you have. The code i
> > gave
> > you is for when you are not using any library.
> >
> > with jquery it would have been as easy as this
> >
> >
> > $("#dicom_image").width();
> > $("#dicom_image").height();
>
> At least for the way I''m following right now. Why am I not getting
the
> value of the width and height returned in my view?
>
> In other words: How can I call the getHeight() and getWidth() Javascript
> functions in my view here?
>
> <canvas id="draw" height="?????"
width="?????" >
> </canvas>
>
> Thanks.
>
>
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radhames brito wrote:
> looks like you are not using any javascript library but are calling a
> prototype method or something
> 
>  var img = document.getElementById("dicom_image");
getElementById is core JavaScript, not a Prototype extension.  If
you''re
going to spread misinformation like this, please do us all a favor and 
stop posting.
> 
> var width = img.clientWidth;
> var height = img.clientHeight;
Best,
-- 
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org

Sent from my iPhone
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@Marnen. I really don''t understand what you mean!
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@Marnen Laibow-Koser

getHeight() and getWidth() are prototype methods.


Read before you accuse me

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he was talking to me,  when you set you called  getHeight() and getWidth()
you used then same names prototype uses, but i didnt notice
you had made your own methods with those name, so he thought that when i
said

radhames brito wrote:
> looks like you are not using any javascript library but are calling a
> prototype method or something
>


i was refering to this

>  var img = document.getElementById("dicom_image");

but i was reffering to this


<%= update_page_tag do |page|
page << "getWidth();"
end
%>

i user this
>  var img = document.getElementById("dicom_image");
to point out that you are not using any libraries but you seem  to be
calling getHeight() and getWidth() that are prototype methods

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radhames brito wrote:
> @Marnen Laibow-Koser
> 
> getHeight() and getWidth() are prototype methods.
> 
...which were not involved in the post you responded to as far as I can 
see.
> 
> Read before you accuse me
I did.

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http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org

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Marnen Laibow-Koser wrote:
> radhames brito wrote:
>> @Marnen Laibow-Koser
>> 
>> getHeight() and getWidth() are prototype methods.
>> 
> ...which were not involved in the post you responded to as far as I can 
> see.
> 
>> 
>> Read before you accuse me
> 
> I did.
> 
> Best,
> -- 
> Marnen Laibow-Koser
> http://www.marnen.org
> marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
> 
> Sent from my iPhone
getWidth() is involved.

If you check my question, you will see the following:

function getWidth() {
  var image = document.getElementById("dicom_image");
  imageWidth = image.width;
  return imageWidth;
  alert("Image Width is " + image.width);
}

Which I then tried to call in "show.html.erb" using:

<%= update_page_tag do |page|
page << "getWidth();"
end
%>
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@Marnen Laibow-Koser

from Abder-Rahman Ali
"getWidth() is involved.

If you check my question, you will see the following:"

i rest my case your honor.

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Abder-Rahman Ali wrote:
> Marnen Laibow-Koser wrote:
>> radhames brito wrote:
>>> @Marnen Laibow-Koser
>>> 
>>> getHeight() and getWidth() are prototype methods.
>>> 
>> ...which were not involved in the post you responded to as far as I can
>> see.
>> 
>>> 
>>> Read before you accuse me
>> 
>> I did.
>> 
>> Best,
>> -- 
>> Marnen Laibow-Koser
>> http://www.marnen.org
>> marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
>> 
>> Sent from my iPhone
> 
> getWidth() is involved.
> 
> If you check my question, you will see the following:
> 
> function getWidth() {
>   var image = document.getElementById("dicom_image");
>   imageWidth = image.width;
>   return imageWidth;
>   alert("Image Width is " + image.width);
> }
> 
> Which I then tried to call in "show.html.erb" using:
> 
> <%= update_page_tag do |page|
> page << "getWidth();"
> end
> %>
OK, then I failed to read properly (helped along by Radhames'' lack of 
proper quoting) and I''m sorry about that.  Apparently I completely 
misunderstood what Radhames was getting at.  I''ll try to read more 
carefully in future.  Radhames, please try to quote more relevant 
material.

Best,
--
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No need to be sorry @Marnen, that''s fine.
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@marnen i comment via gmail, so i forget about the quoting, also , note that
im not a native english speaker and some times my ideas dont come across the
way
i wanted them to.  : /

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radhames brito wrote:
> @marnen i comment via gmail, so i forget about the quoting,
Gmail quotes.  Just use the quoting!
> also , note 
> that
> im not a native english speaker and some times my ideas dont come across 
> the
> way
> i wanted them to.  : /
Understood.  Perhaps if you were to write a little less tersely it might 
be easier to understand.

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ok i found the quotes are

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