OK I get it now :) Thanks very much for your indulgence. Your post is
timely, of course - I just ran into another problem while trying to convert
my code into a plugin. I'm trying to create a plugin that allows me to do
something like this:
$("input").autoSave(function(){ ajax code goes here},{options});
The problem at the moment is that if I use a common function (fn) as the
closure repository, and call the autosave function more than once with
different settings strange things happen. To be expected, really... I'm
thinking I need to store the fn function in a global array, creating a new
object for each element, or at least each call to the plugin but I'm not
certain. Trial and error is all I know :) My code looks like this so far
(createCSSClass is a function by Sam Collett):
jQuery.fn.autoSave = function(fcn,settings) {
settings = jQuery.extend({
delay: 600,
beforeClass: "asBefore",
afterClass: "asAfter"
}, settings);
createCSSClass(".asBefore", "background-color:#FFdddd");
createCSSClass(".asAfter", "background-color:#ddFFdd");
timer = null;
fn = function(e) {
if (e && e.type == 'blur') {
if (timer)
window.clearTimeout(timer);
}
if (this.value != this.title){
fcn();
jQuery(this).removeClass(settings.beforeClass).addClass(settings.afterClass);
}
}
return this.each(function(){
jQuery(this).attr("title",this.value).keyup(function() {
if (this.value != this.title){
if (jQuery(this).is('.' + settings.afterClass))
jQuery(this).removeClass(settings.afterClass);
if (!jQuery(this).is('.' + settings.beforeClass))
jQuery(this).addClass(settings.beforeClass);
var self = this;
timer = window.setTimeout(function()
{fn.apply(self);},settings.delay);
}
}).keydown(function() {
if (timer) window.clearTimeout(timer);
}).blur(fn);
});
};
Any advice?
Blair Mitchelmore-2 wrote:
>
> Functions in JavaScript run at a certain scope. A lot of the time, if
> the function isn't a part of some Object that scope defaults to the
> window object. All JavaScript functions also have two functions that
> allow you to redefine the scope of a function as you call it: apply and
> call. apply takes 2 arguments: the new scope to call the function under
> and an array of arguments to call the function with. call does the same
> thing but instead of an array of arguments, you just supply the
> arguments as additional arguments to that function call.
>
> Example:
> var scope = "Scope";
> var arg = "Arg";
> var fn = function(e) {
> window.alert(this + " => " + e);
> };
> fn(arg); // alerts " => Arg"
> fn.apply(scope,[arg]); // alerts "Scope => Arg"
> fn.call(scope,arg); // alerts "Scope => Arg"
>
> This allows you to redefine the this variable on the fly. Additionally,
> the reason self is used rather than this in fn.apply(self) is because
> 'this' changes scope once you enter a new function. So inside the
> anonymous function defined in the setTimeout call, the scope variable
> 'this' is likely to be the window object. So you have to save a
> reference to the 'this' you want to use as a separate variable so it can
> be referenced elsewhere: hence self = this followed by (inside the
> anonymous function) fn.apply(self).
>
> -blair
>
> Daemach wrote:
>> Yeah that worked. I'm not certain I understand why though :)
>>
>> It does make sense that the closure would actually have to be created
>> inside
>> the event handler but .apply(self) is a new one for me. What exactly is
>> that doing?
>>
>>
>> Blair Mitchelmore-2 wrote:
>>> $(document).ready( function() {
>>> var timer;
>>> var fn = function(e) {
>>> if (e && e.type == 'blur') {
>>> if (timer)
>>> window.clearTimeout(timer);
>>> }
>>> // Do stuff
>>> alert(this.id);
>>> }
>>> $('#test').blur(fn).keyup(function() {
>>> var self = this;
>>> timer = window.setTimeout(function() {
>>> fn.apply(self);
>>> },2000);
>>> }).keydown(function() {
>>> if (timer) window.clearTimeout(timer);
>>> });
>>> });
>
> _______________________________________________
> jQuery mailing list
> [email protected]
> http://jquery.com/discuss/
>
>
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