trigger colorbox on view page load
You may not use the js injector module. Colorbox integrates seamlessly well with views. If you are displaying content as fields in the view (which I think you are) you can use the : 

Fields -> Add 

option to introduce a colorbox trigger. 



For example, Lets consider the below fields : 



The first item "Content : Gallery Image Upload"  has the following settings



The second item "Content : Gallery Image Upload"  has the following settings



and you set up your colorbox trigger like below :



The replacement pattern is all that matters here. If you are
confused what to put for popup, scroll all the way down
to Replacement Patterns and select appropriate field and paste
it in the popup box. Here the trigger field is the the first
"Content : Gallery Image Upload" field and when somebody clicks
it we are introducing a colorbox trigger to start the colorbox
slideshow configured for the second "Content : Gallery Image Upload"
field. 

In short, we are setting up a Gallery here. :)