I have written Javascript to hide both Attach File button from Notes & Attachment related list and Discover Summer 13 button from home page. We need to include the below javascript code in Home page components then we have add this into Home page layout as a Narrow left column.
Then we have to make sure to disable the “Enable Separate Loading of Related Lists” and to enable the “show custom sidebar components on all pages”
function hideBtns() { if(window.location.href.indexOf('.salesforce.com/006')!=-1){ j$("[name*=attachFile]").hide(); }if(window.location.href.indexOf('.salesforce.com/001')!=-1) { j$("[name*=attachFile]").hide(); }if(window.location.href.indexOf('.salesforce.com/003')!=-1){ j$("[name*=attachFile]").hide(); } if(document.getElementsByName('whats_new')[0]!=null) document.getElementsByName('whats_new')[0].style.display = 'hidden'; if(document.getElementsByName('whats_new')[1]!=null) document.getElementsByName('whats_new')[1].style.display = 'hidden'; } if (window.addEventListener) { window.addEventListener('load', hideBtns, false); } else if (window.attachEvent) { window.attachEvent('onload', hideBtns); } function hideBtns() { if(document.getElementsByName('whats_new')[0]!=null) document.getElementsByName('whats_new')[0].style.display = 'none'; if(document.getElementsByName('whats_new')[1]!=null) document.getElementsByName('whats_new')[1].style.display = 'none'; } if (window.addEventListener) { window.addEventListener('load', hideBtns, false); } else if (window.attachEvent) { window.attachEvent('onload', hideBtns); }