While developing your Visualforce pages you may need to be able to obtain the URL of certain actions, s-controls or your static resources.

I found it personally a challenge since the documentation for "URLFOR" function is not included in "Visualforce Developer Guide" itself and instead included in the general help area of Salesforce.

Generally you can use the "URLFOR" function for three purposes:

1. Obtain URL of a s-control
2. Obtain URL of a static resource
3. Obtain URL of an object's action

In this article I will demonstrate usages of the three above.

Generally, URLFOR function returns a relative URL for an action, s-control, or a file in a static resource archive in a Visualforce page. Following the syntax of the function:

{!URLFOR(target, id, [inputs], [no override])}

Parameters shown in brackets ([]) are optional.

• target: You can replace target with a URL or action, s-control or static resource.
• id: This is id of the object or resource name (string type) in support of the provided target.
• inputs: Any additional URL parameters you need to pass you can use this parameter.
  you will to put the URL parameters in brackets and separate them with commas
  ex: [param1="value1", param2="value2"]
• no override: A Boolean value which defaults to false, it applies to targets for standard Salesforce pages. Replace "no override" with "true" when you want to display a standard Salesforce page regardless of whether you have defined an override for it elsewhere.

Obtaining URL of a s-control:

<!-- Use $SControl global veriable to reference your s-control and pass it to the URLFOR function -->
 <apex:outputLink value="{!URLFOR($SControl.MySControlName)}">Link to my S-Control</apex:outputLink> 

Obtaining URL of a Static Resource

<!-- Use $Resource global veriable to reference your resource file -->
<apex:image url="{!URLFOR($Resource.LogoImg)}" width="50" height="50" />

<!-- If your file is in another ZIP file, then pass the path of the file as id to URLFOR -->
<apex:image url="{!URLFOR($Resource.CorpZip, 'images/logo.gif')}" width="50" height="50" />

Obtaining URLs of an Object's Actions:
In order to get URL of the an object's actions you need to know what actions that object supports. Below are some of the common actions most Objects support:

• View: Shows the detail page of an object
• Edit: Shows the object in Edit mode
• Delete: URL for deleting an object
• New: URL to create a new record of an object
• Tab: URL to the home page of an object

However, each object may support additional actions for example Contactalso supports "Clone" action and Case supports "CloseCase" action.

<!-- Use $Action global varialble to access the New action reference -->
<apex:outputLink value="{!URLFOR($Action.Account.New)}">New</apex:outputLink>
<br/>
<!-- View action requires the id parameter, a standard controller can be used to obtain the id -->
<apex:outputLink value="{!URLFOR($Action.Account.view, account.id)}">View</apex:outputLink> 
<br/>
<!-- Edit action requires the id parameter, id is taken from standard controller in this example -->
<apex:outputLink value="{!URLFOR($Action.Account.Edit, account.id)}">Edit</apex:outputLink>  
<br/>
<!-- Delete action requires the id parameter, also a confirm message is added to prevent deleting the record when clicked by mistake -->
<apex:outputLink value="{!URLFOR($Action.Account.delete, account.id)}" onclick="return window.confirm('Are you sure?');">Delete</apex:outputLink> 
<br/>
<!-- From all custom buttons, links, s-controls and visualforce pages you can use the following to get the link of the object's homepage -->
<apex:outputLink value="{!URLFOR($Action.Account.Tab, $ObjectType.Account)}">Home</apex:outputLink>