miscoded

What is it?

User JavaScript is a new feature that lets the user configure Opera to include a specific JavaScript library on all pages. Users who know JavaScript can write their own scripts and share them with others.

What's the point?

This can be used for instance to

• Fix broken pages


• Enhance Opera with your own toolbars / buttons in the page


• Control exactly what the scripts on a page are allowed to do


• Customize and change the page any way you like


• Simplify bookmarklets by adding functions they depend on to the User scripts
  

Security

Before we go into more details, a few words about User JavaScript and security: A user JavaScript file can in no way harm your computer or stored data but badly written files can slow down Opera and malicious files can spy on your browsing. Never install and use a script library from someone you don't know and trust - if in doubt post in the Opera forums, newsgroups or mailing lists and ask if the script you would like to use is well written and exploit-free.

Enabling User JavaScript

This entry in your Opera6.ini file will enable User JavaScript:

[User Prefs]
User JavaScript=1
User JavaScript File=c:\opera\user.js

Adapt the last line to point to the file you want to use.
Opera's "Help / About" screen will tell you what Opera6.ini file is being used, and the address of any active User JavaScript file.


Example

The following user script will enhance mail listings in Hotmail and Yahoo Mail with "QuickSearch" fields similar to those used in Opera's mail client. When you type a word into one of these fields, any mail that does not contain that word in its subject will disappear.

if(window.location.href.indexOf('mail.yahoo.')>-1){
document.addEventListener('load', function(ev){
if(self.name=='ymailmain'){
var inp = document.createElement('input');
inp.addEventListener('keyup', function(){try{
_OUSerJS_to = setTimeout("_Opera_User_JavaScript_quickSearch(document.getElementById('datatable').getElementsByTagName('tr'), '"+this.value+"')", 200);
}catch(e){}
}, false);
var elm = document.getElementById('movetop');
elm.parentNode.appendChild(document.createTextNode('QuickSearch: '));
elm.parentNode.appendChild(inp);
}
}, false);
}

if(window.location.href.indexOf('hotmail.msn')>-1){
document.addEventListener('load', function(ev){
if(document.getElementsByName('hotmail') && self==top){
var inp = document.createElement('input');
inp.addEventListener('keyup', function(){
try{
_OUSerJS_to = setTimeout("_Opera_User_JavaScript_quickSearch(document.getElementsByName('hotmail')[0].getElementsByTagName('tr'), '"+this.value+"' )", 200);
}catch(e){}
}, false);
var elm = document.getElementsByName('hotmail')[0];
elm.insertBefore(inp, elm.firstChild);
elm.insertBefore(document.createTextNode('QuickSearch: '), elm.firstChild);
}
}, false);
}

function _Opera_User_JavaScript_quickSearch(nodeList, text){
for(i = 0; i < nodeList.length; i++){
if (nodeList.innerText.indexOf(text) == -1 ){
nodeList.style.display = 'none';
}else {
nodeList.style.display = '';
}
}
}


(You may have to fix some linewrapping in the last example. Also note that it may fail if Hotmail or Yahoo one day update their code..)