javascript - Why doesn't this method call work from within a prototype? -

javascript - Why doesn't this method call work from within a prototype? -

i'm trying larn how write improve javascript i'm not sure why doesn't work. have 2 method calls write text field. first 1 works fine, sec 1 doesn't. why text field variable undefined going thorough nested call? help appreciated:

(function () { var testobj = function (logel) { this.log = logel; }; testobj.prototype = function () { var log1 = function (text) { this.log.val(text); }; var log2 = function (text) { log1(text); } homecoming { log1: log1, log2: log2 }; }(); $(function () { var logel = $("#log"); var test = new testobj(logel); test.log1("this works"); test.log2("this dosen't"); //this.log undefined }); })()

as dc5 , hayes pointed out value of this invoking object. it's object comes before function:

somebutton.click();//this somebutton click();//nothing before click, window assumed or throw exception in strict mode myobject.dosomething();//this in dosomething myobject

since log1 available through closures doesn't throw exception (log1 undefined) this in log1 function window since log2 didn't provide invoking object.

to set invoking object alter code to:

log1.call(this,text);

i'm not big fan of throwing including kitchen sink in iife creates unneeded closures every method. can wrap application an object literal instead , utilize iife need closures:

var app ={ testobj:function(...

log1 won't available through closures in log2 can phone call using this

this.log1(text);

more on prototype, constructor functions, inheritance , value of this can found here.

javascript