Access ruby array in javascript

Question

I want to access a Ruby array in javascript. Please tell me the method to do that. My array is holding the result of a sql query.

  @contacts = Contact.order("contacts.position ASC")

I am trying to do this....

for(var i=0; i< a; i++)
    {   
        var firstnameV = "<%=Contact.order('contacts.position ASC')[i].first_name%>";
        var lastnameV = "<%=Contact.order('contacts.position ASC')[i].last_name%>";
        var emailV = "<%=Contact.order('contacts.position ASC')[i].email%>";
        var contactV = parseInt("<%=Contact.order('contacts.position ASC')[i].contact_no%>";
        var posV = parseInt("<%=Contact.order('contacts.position ASC')[i].position%>";  
        tx.executeSql('INSERT INTO contact_table (firstname, lastname, email, contact, pos)
        VALUES (firstnameV,lastnameV, emailV, contactV, posV)');
    }

@apneadiving Could you please show the steps. I am totally new at rails and ajax. — rdp
– rdp, Commented Feb 3, 2011 at 9:07

Arjan · Accepted Answer · 2011-02-12 12:44:30Z

4

Quick example of how you can render the value of Ruby variable to JavaScript. Add <%= yield :head %> to head tag in views/layouts/application.html.erb. Then in views/contacts/index.erb (or whatever view you use) add the following:

<%content_for :head do %>
<script type="text/javascript">
window.onload = function() {
    alert("First contact in database is <%=Contact.order('contacts.position ASC').first.name%>")
}
</script>
<%end%>

This will alert the first contact name from your database.

edited Feb 12, 2011 at 12:44

Arjan

23.8k12 gold badges65 silver badges71 bronze badges

answered Feb 3, 2011 at 9:57

Nikita Barsukov

2,9945 gold badges33 silver badges40 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

rdp Over a year ago

@Nikita: How am I suppose to select a particular element for the array. For eg.When I try to do this <%=Contact.order('contacts.position ASC')[i].first.name%> it shows error. A constant in the place of 'i' works fine. The error is undefined local variable i.

Nikita Barsukov Over a year ago

@dilip - OK, it gets a bit more advanced. <% somecode %> in view executes ruby code. <%= ruby variable %> (note = sign) inserts value of ruby variable to the html code in view. So one option for you can be constructing a loop and then inserting it to your view with <% %>

rdp Over a year ago

@nikita: I know how to add ruby variables to html code. But here i want to assign ruby variable to javascript variable. I tried doing this var first = "<%=Contact.order('contacts.position ASC')[i].first_name%>"; But it works only if i give a contant number in the place of i. Else it shows local variable undeclared.

Nikita Barsukov Over a year ago

Exactly. var first = is outside <% %> so it will be parsed as a part of html code, not as Ruby code. Use something like <% i = 5 %><%=Contact.order('contacts.position ASC')[i].first_name%> or even a loop, depending what you want.

Nikita Barsukov Over a year ago

<% @contacts = Contact.order("contacts.position ASC") %><%a = 10%><% for i in 0 do %>var firstname = <%=@contacts[i].first_name%><%end%>

|

Tarscher · Accepted Answer · 2011-02-03 09:00:23Z

1

You can do this by using the

to_json

method in Ruby

or

render :json => @contacts

answered Feb 3, 2011 at 9:00

Tarscher

1,9332 gold badges22 silver badges45 bronze badges

1 Comment

rdp Over a year ago

After that how am I suppose to use it in javscript? I am totally new to rails.

Radek · Accepted Answer · 2011-02-03 08:51:19Z

0

Ruby is server side language. JavaScript is mostly (server side also - e.g. node.js) client side. If you want to pass values from Ruby to JS, you could render that value as part of view in script tags or retrieve them via AJAX.

answered Feb 3, 2011 at 8:51

Radek

8,3614 gold badges34 silver badges42 bronze badges

1 Comment

Radek Over a year ago

@Tarscher gave you an example in his answer :) And I suggest reading about JSON: json.org

Collectives™ on Stack Overflow

Access ruby array in javascript

3 Answers 3

9 Comments

1 Comment

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

9 Comments

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related