// form_autofocus.js
//
// To use, place this file within your Web site, and include the following in
// the <head> section of your document, with $PATH changed to the URL path
// (Web address, not internal path name) where you have installed this file:
//
// <script type="text/javascript" src="/$PATH/form_autofocus.js"></script>
//
// This script will automatically move the input focus (the user's cursor) to
// what looks like the most reasonable place for it. The script's order of
// preference for where it will move focus is:
//
// 1) Empty text, textarea, and password inputs
// 2) Text, textarea, and password inputs with text in them
// 3) File inputs
// 4) Select inputs (single or multiple)
// 5) Radio button and checkbox inputs
//
// Input focus is moved using the onload event, and so will occur when page
// load is complete. If it appears that the user has interacted with the
// page -- if any form inputs are not in their default state, including
// hidden inputs -- focus will not be changed. This is to avoid the annoying
// case where you've already started typing into a form input, but a script
// interferes with what you're doing.
//
// The script will select the first input it encounters (in the order they
// are reported by the browser, which is generally the order they were
// defined in) out of the most preferred type of input it finds. Non-visible
// form elements are excluded from consideration entirely, since focus cannot
// be successfully moved to them.
//
// You can alter the script's behavior in four ways.
//
// 1) You can set the variable document.focusOverride to a form input
// object; this will make the script focus on that input instead of one
// it selects.
// 2) You can include the class 'nofocus' on inputs; this will make the
// script skip them for purposes of selecting what to focus on.
// 3) You can include the class 'wantfocus' on inputs; the script will
// preferentially select inputs with this class. (If two inputs both
// have 'wantfocus', the preference list above applies to them.)
// 4) You can include the class 'focusignore' on inputs. This makes the
// script ignore the input for purposes of determining whether the user
// has interacted with the page.
//
// This script is known to work under IE 6, IE 7, Firefox 2, and Safari 3.
// This includes handling the case where a window is opened in a new tab that
// does not immediately receive window focus, which requires special treatment
// for some browsers.
//
// Official home: http://lostsouls.org/grimoire_form_autofocus. Any updates
// will be found there.
//
// v1.0 2007-09-24, Chaos of Lost Souls MUD, http://lostsouls.org/
// v1.1 2007-10-05, Chaos: refactoring, cleanup, unload on completion
// v1.1.1 2007-12-25, Chaos: don't break if a form element has no classname
// v1.2 2008-06-03, Chaos: detecting and handling non-visible form elements
// v1.2.1 2008-07-02, Chaos: fixed logic error on multiple select boxes
//
// This code is released into the public domain.
// This information is provided AS IS and any express or implied warranties,
// including, but not limited to, the implied warranties of merchantability
// and fitness for a particular purpose are disclaimed. In no event shall the
// author or publisher be liable for any damages of any kind, however caused
// and on any theory of liability, arising in any way out of the use of this
// information, even if advised of the possibility of such damage.
if(window) {
var formAutoFocus = function() {
var focusTarget;
var focusFlag;
var focusDone = function() {
focusFlag = true;
}
var attachFocus = function() {
if(focusTarget.attachEvent) {
focusTarget.attachEvent('onfocus', focusDone);
} else {
focusTarget.prevOnFocus = focusTarget.onfocus;
if(focusTarget.prevOnFocus) {
var dualFocus = function() {
focusTarget.prevOnFocus();
focusDone();
}
focusTarget.onfocus = dualFocus;
} else {
focusTarget.onfocus = focusDone;
}
}
}
var detachFocus = function() {
if(focusTarget.attachEvent) {
focusTarget.detachEvent('onfocus', focusDone);
} else {
focusTarget.onfocus = focusTarget.prevOnFocus;
focusTarget.prevOnFocus = null;
}
}
var checkFocus = function() {
detachFocus();
if(focusFlag)
window.formAutoFocus = null;
else
window.setTimeout(formAutoFocus, 50);
}
var tryFocus = function(obj) {
focusTarget = obj;
focusFlag = false;
attachFocus();
try {
focusTarget.focus();
} catch(error) {
return;
}
if(focusFlag) {
detachFocus();
formAutoFocus = null;
return;
}
window.setTimeout(checkFocus, 10);
}
var skip = function(obj) {
return elem.classname && elem.classname.match(/\bfocusignore\b/);
}
if(document.focusOverride) {
tryFocus(document.focusOverride);
return;
}
var tiers = new Array;
for(var i = 0; i < document.forms.length; i++) {
var form = document.forms[i];
for(var j = 0; j < form.elements.length; j++) {
var elem = form.elements[j];
if(!elem.focus)
continue;
if(!elem.offsetWidth)
continue;
var tier;
switch(elem.type) {
case 'text' :
case 'textarea' :
case 'password' :
if(elem.value != elem.defaultValue && !skip(elem))
return;
tier = elem.value ? 1 : 0;
break;
case 'file' :
if(elem.value != elem.defaultValue && !skip(elem))
return;
tier = 2;
break;
case 'select-one' :
if(!skip(elem)) {
var anyDefault = false;
for(var k = 0; k < elem.options.length; k++) {
if(elem.options[k].defaultSelected) {
anyDefault = true;
break;
}
}
if(anyDefault) {
for(var k = 0; k < elem.options.length; k++) {
var opt = elem.options[k];
if(opt.selected != opt.defaultSelected)
return;
}
} else {
if(elem.selectedIndex != 0)
return;
}
}
tier = 3;
break;
case 'select-multiple':
if(!skip(elem)) {
for(var k = 0; k < elem.options.length; k++) {
var opt = elem.options[k];
if(opt.selected != opt.defaultSelected)
return;
}
}
tier = 3;
break;
case 'radio' :
case 'checkbox' :
if(elem.selected != elem.defaultSelected && !skip(elem))
return;
tier = 4;
break;
case 'hidden' :
if(elem.value != elem.defaultValue && !skip(elem))
return;
continue;
default :
continue;
}
if(!tiers[0] && !elem.className.match(/\bnofocus\b/)) {
var wantfocus = elem.className.match(/\bwantfocus\b/);
if(!wantfocus)
tier += 5;
if(!tiers[tier])
tiers[tier] = elem;
}
}
}
for(var ix = 0; ix < tiers.length; ix++) {
if(tiers[ix]) {
tryFocus(tiers[ix]);
break;
}
}
}
if(window.attachEvent) {
window.attachEvent('onload', formAutoFocus);
} else {
if(window.onload) {
var curronload = window.onload;
var newonload = function() {
curronload();
formAutoFocus();
};
window.onload = newonload;
} else {
window.onload = formAutoFocus;
}
}
}