show table borders:
javascript:x=document.getElementsByTagName("table");for(i=0;i<x.length;i++){void(x[i].border=1)}

hide table borders:
javascript:x=document.getElementsByTagName("table");for(i=0;i<x.length;i++){void(x[i].border=0)}

text only mode:
javascript:document.body.innerHTML = document.body.innerText

enable right click:
javascript:void(window.onmousedown='');void(document.onmousedown='');void(document.body.onmousedown='');void(window.onmouseup='');void(document.onmouseup='');void(document.body.onmouseup='');void(window.oncontextmenu='');void(document.oncontextmenu='');void(document.body.oncontextmenu='');for(i=0;i<document.images.length;i++){void(document.images[i].onmousedown='')}

form inspector:
javascript:void(w=window.open("","w","width=400,height=400,resizable,scrollbars=yes,no"));w.document.write("<title>Form Info</title><st"+"yle>u{cursor:hand;}td{font-family:verdana;font-size:12px;}td.fheader{font-weight:bold;}</style><table width='360'><tr><td class='fheader'>#</td><td class='fheader'>Name</td><td class='fheader'>Action</td><td class='fheader'>Method</td><td class='fheader'>Elements</td><td> </td></tr>");for(i=0;i<document.forms.length;i++){F=document.forms[i];void(w.document.write("<tr><td><"+"u onClick=x("+i+");self.blur();>"+i+"</u"+"></td><td><"+"u onClick=x("+i+");self.blur();>"+F.name+"</u"+"></td><td><"+"u onClick=x("+i+");self.blur();>"+F.action+"</u"+"></td><td><"+"u onClick=x("+i+");self.blur();>"+F.method+"</u"+"></td><td><"+"u onClick=x("+i+");self.blur();>"+F.elements.length+"</u"+"></td><td><input type='button' onClick='window.opener.document.forms["+i+"].submit();' value='submit'></td></tr>"))};w.document.write("</table>");w.document.write("<scr"+"ipt>function y(){if(!confirm('Browse Another Form?')){self.close();}}function x(formNum){void(w2=window.open('','w2','width=400,height=400,resizable,scrollbars=yes,no'));f=window.opener.document.forms[formNum];if(f){El = f.elements;w2.document.write('<st'+'yle>textarea{border: 1px solid black;}td{font-family:verdana;font-size:12px;}td.fheader{font-weight:bold;}</style><table><tr><td class=fheader>Form Name:</td><td colspan=2>'+f.name+'</td></tr><tr><td class=fheader>Form Action:</td><td colspan=2>'+f.action+'</td></tr><tr><td colspan=3> </td></tr><tr><td colspan=3 class=fheader>Elements:</td></tr><tr><td class=fheader>name</td><td class=fheader>type</td><td class=fheader>value</td></tr>');for(i=0 ; i<El.length ; i++){w2.document.write('<tr><td>'+El[i].name+'</td><td>'+El[i].type+'</td><td><textarea onKeyUp=window.opener.window.opener.document.forms['+formNum+'].elements['+i+'].value=this.value>'+El[i].value+'</text'+'area></td></tr>');}w2.document.write('</table><scr'+'ipt>window.onbeforeunload=window.opener.y;</scr'+'ipt>');}}</script>");

google:
javascript:q=(document.frames.length?'':document.selection.createRange().text);for(i=0;i<document.frames.length;i++){q=document.frames[i].document.selection.createRange().text;if(q!='')break;}if(q=='')void(q=prompt('Enter text to search using Google. You can also highlight a word on this web page before clicking Google Search.',''));if(q)location.href='http://www.google.com/search?q='+escape(q)+'&num=100'

hide images:
javascript:for(i=0;i<document.images.length;i++){void(document.images[i].style.display='none')}void(document.body.style.background='none');

show Images:
javascript:for(i=0;i<document.images.length;i++){void(document.images[i].style.display='inline')}

lock page:
javascript:do{void(pass=prompt("Choose Unlock Code",""))} while(pass=="");if(pass){t=document.title;document.title='LOCKED';self.moveTo(50,-100);void(x=document.body.innerHTML);void(document.body.innerHTML="<table bgcolor='black' width='100%' height='100%'><tr><td valign='bottom' align='center'><h1 style='letter-spacing:30px;font-family:verdana;width:100%;color:red;text-align:center;'>LOCKED</h1><br /><br /></td></tr></table>");void(p='');for(i=0,m='';p!=pass;i++){void(p=prompt("Enter Unlock Code:\n"+m,''));m="Attempted Entries: "+(i+1);}void(document.body.innerHTML=x);void(self.moveTo(10,10));void(document.title=t);}

off site links open in new window:
javascript:thissite=document.location.hostname;for(i=0;i<document.links.length;i++){if(document.links[i].protocol=="http:" && document.links[i].hostname!=thissite){void(document.links[i].target='_blank');}}

DOM inspector:
javascript:void(m=window.open("","m","width=400,height=500,resizable,no"));m.document.write("<script>function%20x(s){var%20o=eval(s),b='';for(v%20in%20o){b+='<tr><td>'+(typeof%20o[v]=='object'%20&&%20o[v]!=null?'<A%20HREF=javascript:top.x(\"'+s+(isNaN(v)?'.'+v:'['+v+']')+'\")>'+v+'</A>':v)+'</td><td>'+(typeof%20o[v]=='unknown'?'_':'<xmp>'+o[v]+'</xmp>')+'</td></tr>'}fd=frames[0].document;fd.write('<h3>'+s+'</h3><table%20border=1>'+b+'</table>');fd.close();}</script><frameset><frame></frameset>");m.x('opener')

edit Cookie:
javascript:void(document.cookie=prompt("Enter Cookie Values:",document.cookie));

set page title:
javascript:void(document.title=prompt("New Title:",document.title))

view source:
javascript:self.location = "view-source:"+prompt("Enter Page to view",self.location);