SharePoint 2007 Built-in JS Functions

//Get Current User ID  i.e - alert(_spUserId);

_spUserId

//Run JS Function on Page Load

_spBodyOnLoadFunctionNames.push('FunctionName');

//First we must call the EnsureSetup method

JSRequest.EnsureSetup();

//Get a query string parameter called ItemId. i.e - "page.aspx?ItemId=11" will return 11

itemId = JSRequest.QueryString["ItemId"];

//Get the current page name. i.e - "default.aspx"

pageName = JSRequest.FileName;

//Get the current path name. i.e - "/doclib/default.aspx"

path = JSRequest.PathName;