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How can I read ‘native code’ JavaScript functions?
(3 answers)
Closed 6 years ago.
How can I see how native js functions are implemented in a browser?
I've tried Math.floor.toString() but it returns "function floor() { [native code] }" and I can't step into the function using debugger.
You can't do this from the console, because the functions are part of the compiled browser executable … or, rather, its JavaScript engine. It is native code.
You may be able to read the source code for that engine, though, depending on which browser you're using. For example, Chrome's v8 source is on GitHub.
Updated
It's a native function. I'm guessing you could download the source code for a browser, as that's where it's implemented
Firefox Source code for example
Related
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How do I use Document Object Model (DOM) in VScode?
(4 answers)
Closed 7 months ago.
Whenever I try to access the document object in vs code I get ReferenceError: document is not defined. It seems the problem is code running in node.js which doesn't have the document thing.
My question is how do I set the vs code to run on the browser only, to be able to access DOM elements. I have installed Live server extension but the code still runs in node.js which gets me the error and I can`t properly check if the code is working the way I want.
So please.. How do I solve this problem?
How do I change the runtime environment in vs code?
You don't need a server to do this.
Open the HTML file directly inside of the browser.
It will execute your scripts as Common JS.
This question already has answers here:
Call Python function from JavaScript code
(6 answers)
Closed 3 years ago.
I have this python method shown below in a separate file and want to access and get value using plain js (no frame works used.) is there any way i can achieve this?
def myPythonCode :
....
...
return somevalue
You can use python wrapper for google V8 engine called PyV8
It act as a bridge between the Python and JavaScript objects, and support to hosting Google's v8 engine in a python script.
This question already has answers here:
Where can I find javascript native functions source code? [duplicate]
(3 answers)
Closed 1 year ago.
For example, i want to know how the querySelector method was built. I checked on MDN but there's only examples that show how to use it.
I also tried to check in the console.log but nothing readable.
There is a non-standard method to do this. Please be aware that it is not fully cross-browser compatible and shouldn't be used in a production environment.
function hello(){
return "Hi!";
}
console.log(hello.toSource());
See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/toSource for more.
Edit:
To see the source code of a built-in function, you will need to look at the engine source. This varies browser to browser. For example, Chrome uses the V8 engine. See https://github.com/v8/v8
This question already has answers here:
Object.defineProperty alternative for IE8
(2 answers)
Closed 8 years ago.
I'm working on a JSON Query language, project which is working fine in every browser except IE8.
I'm getting this Object doesn't support this action in IE8.
Object.defineProperty(FJQL, c, {
get: function(){
return (new Query(this, this.records))[c];
}
});
Is there any alternative solution to this?
Thanks....
IE8 does not support getter/setter functions on properties of non DOM objects.
So here you would need to use full getter functions
Please have a look through here.It gives you Answer.:)
This question already has answers here:
What does ‘::’ (double colon) do in javascript for events?
(6 answers)
Double colons in function declaration in Javascript?
(1 answer)
Closed 9 years ago.
I recently came upon this code on the web :
function window::onload() {
alert('onload!');
}
This (strange) syntax is only working in Internet Explorer (IE 8 in my case) and I wasn't sure of how it was called so I could search for it.
I simply want to know if there is some documentation related to this type of functions and if so, how are they called ?
That is automatic event binding in JScript, similar to the Object_EventName naming convention in VBScript.
See: Scripting Events
Supposedly it has meen removed in later version of Internet Explorer, just as some other rarely used non-standard features.
MS-ES5EX ECMAScript extension for Event Handler Function Definitions
http://msdn.microsoft.com/en-us/library/ff955429.aspx