Javascript with Salesforce - Example 1

// This Javascript snippet can be used on a custom button to pass a parameter to a report allowing dynamic reports. 
// window.open("salesforce_instance.com/reportId?firstparamater)
// More info on using Javascript behind custom buttons to create dynamic reports can be found here: http://www.tgerm.com/2011/04/passing-params-to-reports-salesforce.html 

window.open("https://eu0.salesforce.com/00O11000000P42z?pv0={!Account.Id}", "Key_Contacts", "toolbar=0, scrollbars=1");