I've seen several solutions for passing variables via a URL string.
I'm just wondering how you can find these variables.
For example, there are some that have explained as below.
I'm trying to find the 'Call Type' variable on a task to pass in the URL string.
This one listed below is for just 'Type'.
Type: &tsk10={!text} (The text you type in here must be a value in the picklist)
example string:
https://na6.salesforce.com/00T/e?title=Call&who_id=!User.Id}&00N800000004wDKu=Marketing&what_id={!Account.Id}&tsk3=!Account.Name}&tsk5=Call&tsk12=Completed&retURL=%2F{Account.Id}
Best Answer
Use a chrome browser right click and say inspect element.
Say for eg. you want to include the name of the field "website" for using in your URL param
Right click on the website input field and you should the screen split into half and show the raw code like
Use the Id in your URL acc12_ileinner= "yahoo.com"