I'm currently delving into object oriented programming in JavaScript.
function doStock() { //my class
var that = this;
var nAntiFreeze = null; // timeout ID
var getContent = function(oInPageContainer) {
GM_log('Antifreeze, before clear ' +nAntiFreeze);
//clearTimeout(nAntiFreeze);
GM_log('Antifreeze, after clear ' +nAntiFreeze);
};
return {
sLink : "",
oList : "",
sSplitOperator : ";",
reset : function() {
this.sLink = '';
this.oList = '';
this.sSplitOperator = ';';
nAntiFreeze = null;
},
loadPage : function() {
if (this.sLink.length == 0) return;
if (this.oList.length == 0) return;
nAntiFreeze = setTimeout(function(){GM_log(that); that.loadPage();},30000);
GM_log('antifreeze ' + nAntiFreeze);
getPageAsync2(this.sLink,false,getContent); //GM_xmlhttprequest
}
}
};
My script operates on GreaseMonkey in Firefox 4. Within my code, I utilize the above function/class to create an object like so:
var oStocker = new doStock();
oStocker.sLink = 'www.somepage.com';
oStocker.oList = 'some list, possibly a string line or an array object';
oStocker.loadPage();
The getPageAsync2 function invokes GM_xmlhttprequest and then delivers the result page contents within a div container to the callback function.
Initially, a general query arises: why does the value of nAntiFreeze not revert to null or any other value after calling the clearTimeOut function?
Secondly, why do I encounter the error
that.loadPage() is not a functionA previous respondent managed to resolve their issue by utilizing var that = this. Why doesn't it work for me?
Custom Object calling Methods with setTimeout loses scope
EDIT: Thirdly, what happens if I generate a million objects? Will the browser dispose of them once they're finished working? Considering this object utilizes asynchronous ajax calls, I can't simply do
var oStocker = new doStock();
oStocker.loadPage();
oStocker = null;
The line oStocker = null will be executed before my object even completes its tasks.
Thank you