CODEWITHSUNDEEP
javascriptruby-on-railsruby-on-rails-3.1
hyperrjas
hyperrjas

Reputation: 10744

How to add JavaScript to input field

I have this input field in Rails 3.1:

<%=f.file_field :image, :id => "upload"%>

I want to add this JavaScript before the input field:

onchange="readURL(this);

How can I do this?

Must see in HTML sth like:

<input type="file" onchange="readURL(this); name="post[image]" id="upload">

Upvotes: 2

Views: 3217

Answers (2)

Syed Aslam
Syed Aslam

Reputation: 8807

Are you using JQuery? 

$("#upload").change(function() { 
  ..
});

is one way and 

$("#upload").bind("change", function() {
  ..
});

is another.

JQuery Doc.

Update:

You can write it as: 

<%= f.file_field :image, :id => "upload", :onchange => "readURL(this)" %>

This will give you HTML something like:

<input type="file" onchange="readURL(this); return false;" name="post[image]" id="upload">

Upvotes: 2

Kyle Smith
Kyle Smith

Reputation: 2332

The preferred way to do this is via unobtrusive JavaScript (essentially adding JavaScript functionality to a page after the DOM is loaded, and making it optional). In rails 3.1 and later, you want to add the JS code in Syed's answer to app/assets/javascript/controller_name.js.coffee or similiar.

Upvotes: 0

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