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Razor Syntax in External Javascript

So as you might know, Razor Syntax in ASP.NET MVC does not work in external JavaScript files.
My current solution is to put the Razor Syntax in a a global variable and set the value of that variable from the mvc view that is making use of that .js file.
JavaScript file:
function myFunc() {
alert(myValue);
}
MVC View file:
<script language="text/javascript">
myValue = #myValueFromModel;
</script>
I want to know how I can pass myValue directly as a parameter to the function ? I prefer to have explicit calling with param than relying on globals, however I'm not so keen on javascript.
How would I implement this with javascript parameters? Thanks!

Just have your function accept an argument and use that in the alert (or wherever).
external.js
function myFunc(value) {
alert(value);
}
someview.cshtml
<script>
myFunc(#myValueFromModel);
</script>
One thing to keep in mind though, is that if myValueFromModel is a string then it is going to come through as myFunc(hello) so you need to wrap that in quotes so it becomes myFunc('hello') like this
myFunc('#(myValueFromModel)');
Note the extra () used with razor. This helps the engine distinguish where the break between the razor code is so nothing odd happens. It can be useful when there are nested ( or " around.
edit
If this is going to be done multiple times, then some changes may need to take place in the JavaScript end of things. Mainly that the shown example doesn't properly depict the scenario. It will need to be modified. You may want to use a simple structure like this.
jsFiddle Demo
external.js
var myFunc= new function(){
var func = this,
myFunc = function(){
alert(func.value);
};
myFunc.set = function(value){
func.value = value;
}
return myFunc;
};
someview.cshtml
<script>
myFunc.set('#(myValueFromModel)');
myFunc();//can be called repeatedly now
</script>

I often find that JavaScript in the browser is typically conceptually tied to a specific element. If that's the case for you, you may want to associate the value with that element in your Razor code, and then use JavaScript to extract that value and use it in some way.
For example:
<div class="my-class" data-func-arg="#myValueFromModel"></div>
Static JavaScript:
$(function() {
$('.my-class').click(function() {
var arg = $(this).data('func-arg');
myFunc(arg);
});
});

Do you want to execute your function immediately? Or want to call the funcion with the parameter?
You could add a wrapper function with no parameter and inside call your function with the global var as a parameter. And when you need to call myFunc() you call it trough myFuncWrapper();
function myFuncWrapper(){
myFunc(myValue);
}
function myFunc(myParam){
//function code here;
}

Inject an opened window with script

This question asks for a way to open a new window using window.open and then inject it with a script. It was not possible because of cross-domain security issues.
However, my problem is that I want to do the exact same thing, except from the same domain to the same domain. Is this possible?
Note that .write does not solve this problem because it wipes all the html from the page first.

You can do something like this:
var theWindow = window.open('http://stackoverflow.com'),
theDoc = theWindow.document,
theScript = document.createElement('script');
function injectThis() {
// The code you want to inject goes here
alert(document.body.innerHTML);
}
theScript.innerHTML = 'window.onload = ' + injectThis.toString() + ';';
theDoc.body.appendChild(theScript);
This also seems to work:
var theWindow = window.open('http://stackoverflow.com'),
theScript = document.createElement('script');
function injectThis() {
// The code you want to inject goes here
alert(document.body.innerHTML);
}
// Self executing function
theScript.innerHTML = '(' + injectThis.toString() + '());';
theWindow.onload = function () {
// Append the script to the new window's body.
// Only seems to work with `this`
this.document.body.appendChild(theScript);
};
And if for some reason you want to use eval:
var theWindow = window.open('http://stackoverflow.com'),
theScript;
function injectThis() {
// The code you want to inject goes here
alert(document.body.innerHTML);
}
// Self executing function
theScript = '(' + injectThis.toString() + '());';
theWindow.onload = function () {
this.eval(theScript);
};
What this does (Explanation for the first bit of code. All examples are quite similar):
Opens the new window
Gets a reference to the new window's document
Creates a script element
Places all the code you want to 'inject' into a function
Changes the script's innerHTML to load said function when the window
loads, with the window.onload event (you can also use addEventListener). I used toString() for convenience, so you don't have to concatenate a bunch of strings. toString basically returns the whole injectThis function as a string.
Appends the script to the new window's document.body, it won't actually append it to the document that is loaded, it appends it before it loads (to an empty body), and that's why you have to use window.onload, so that your script can manipulate the new document.
It's probably a good idea to use window.addEventListener('load', injectThis.toString()); instead of window.onload, in case you already have a script within your new page that uses the window.onload event (it'd overwrite the injection script).
Note that you can do anything inside of the injectThis function: append DIVs, do DOM queries, add even more scripts, etc...
Also note that you can manipulate the new window's DOM inside of the theWindow.onload event, using this.

Yes...
var w = window.open(<your local url>);
w.document.write('<html><head>...</head><body>...</body></html>');

Here's a trick I use, it uses query strings, and is client side. Not perfect but it works:
On the sending page, do:
var javascriptToSend = encodeURIComponent("alert('Hi!');");
window.open('mypage.html?javascript=' + javascriptToSend);
Replace mypage.html with your page. Now on the receiving page, add:
(location.href.match(/(?:javascript)=([^&]+)/)[1])&&eval(decodeURIComponent(location.href.match(/(?:javascript)=([^&]+)/)[1]));
You'll have to do some back-and forth to make sure this works.
If you HAVE PHP you can use this more reliable solution on the receiving page:
eval(decodeURIComponent(<?=$_GET['javascript'] ?>));

Override/Rewrite a javascript library function

I am using an open source javascript library timeline.verite.co
It's a timeline library which works great on page load. But when I try to repaint the timeline on certain condition, it starts giving out weird errors
I would like to modify the init function in the library. But instead of changing it in the original library itself, I would like to rewrite/override this function in another separate .js file so that when this function is called, instead of going to the original function, it must use my modified function.
I'm not sure whether to use prototype/ inheritance and how to use it to solve this problem?

You only need to assign the new value for it. Here is an example:
obj = {
myFunction : function() {
alert('originalValue');
}
}
obj.myFunction();
obj.myFunction = function() {
alert('newValue');
}
obj.myFunction();

Function (..) throws 'eval is evil' message

I'm not using eval, and I'm not sure what the problem is that Crockford has with the following. Is there a better approach to solve the following problem or is this just something I need to ignore (I prefer to perfect/improve my solutions if there is areas for improvement).
I'm using some pixel tracking stuff and in this case a client has bound a JS function to the onclick property of an HTML image tag which redirects off the site. I need to track the clicks reliably without running into race conditions with multiples of event listeners on the image. The strategy is to override the event at run time, copying and running it in my own function. Note this is being applied to a site I do not control and cannot change. So the solution looks something like:
...
func = Function(img.attr('onclick'));
...
img.attr('onclick', '');
... //some custom tracking code
func.call(this);
and the JSLint checker throws the eval is evil error.
Is there a better way to avoid race conditions for multiple events around href actions?

You're implicitly using eval because you're asking for the callback function as it was specified as an attribute in the HTML as a string and then constructing a Function with it.
Just use the img.onclick property instead, and you will directly obtain the function that the browser built from the attribute that you can then .call:
var func = img.onclick; // access already compiled function
img.onclick = null; // property change updates the attribute too
... // some custom tracking code
func.call(img, ev); // call the original function
or better yet:
(function(el) {
var old = el.onclick;
el.onclick = function() {
// do my stuff
..
// invoke the old handler with the same parameters
old.apply(this, arguments);
}
})(img);
The advantage of this latter method are two fold:
it creates no new global variables - everything is hidden inside the anonymous closure
It ensures that the original handler is called with the exact same parameters as are supplied to your replacement function

var oldClick = myImg.onclick;
myImg.onclick = function(evt){
// Put you own code here
return oldClick.call( this, evt );
};

Adding onclick and additional code to a .js document

I have a pretty specific question. I am trying to implement an onclick and cross domain tracking within a block of text, but it looks like it may need to be put directly into a .js document. I don't have a lot of JS experience. Basically, the current code looks like:
// JavaScript Document
function popup_no_status(loc)
{
var windowW=1000
var windowH=700
s = "width="+windowW+",height="+windowH+",status=yes, resizable=yes, scrollbars=yes";
mywin = window.open(loc ,'CBE', s);
mywin.focus();
}
What I want to add to this is:
onclick="pageTracker._trackEvent('Button', 'Click', 'QuickSearchWidget'); pageTracker._link(this.href); return false;
Can I just add it to the end of the document before the closing bracket? Any Ideas?
Much appreciated!

As long as the object pageTracker is defined and instantiated, you can call its methods like any other function:
function popup_no_status(loc) {
var s = "width=700,height=1000,status=yes, resizable=yes, scrollbars=yes";
var mywin = window.open(loc ,'CBE', s);
mywin.focus();
pageTracker._trackEvent('Button', 'Click', 'QuickSearchWidget');
pageTracker._link(this.href);
}
Also, the variables windowW and windowH are pointless in your example code - there is no need to store the string values in a variable if all you're going to do is concatenate them into another string. Further, unless you intend the mywin and s variables to be global, you should use the var keyword before defining them - that restricts the variables to the function scope instead of the global scope (all variables declared in a function without the var keyword are considered global).
If the code above gives an error like ReferenceError: pageTracker is not defined, that means that the code in which the pageTracker object is defined is either not included on the page, or it has not been instantiated.
Now... as for onClick, I am not clear what you're after here. Do you want this function to run when someone clicks the document? That would get pretty annoying!