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How to fix “Headers already sent” error in PHP
...
Unintentional:
Whitespace before <?php or after ?>
The UTF-8 Byte Order Mark specifically
Previous error messages or notices
Intentional:
print, echo and other functions producing output
Raw <html> sections prior <?php code.
Why does it happen?
To understand why header...
When and why are database joins expensive?
... bulk disk reads which are the most expensive aspect of the exercise by an order of magnitude. Performing a join, by contrast, logically requires retrieval of only the keys. In practice, not even the key values are fetched: the key hash values are used for join comparisons, mitigating the cost of mu...
Why doesn't the height of a container element increase if it contains floated elements?
...k -->
<div style="clear: both;"></div>
<!-- Now in order to prevent the next div from floating beside the top ones,
we use `clear: both;`. This is like a wall, so now none of the div's
will be floated after this point. The container height will now also includ...
When is JavaScript synchronous?
...ous means one at a time i.e. one line of code is being executed at time in order the code appears. So in JavaScript one thing is happening at a time.
Execution Context
The JavaScript engine interacts with other engines in the browser.
In the JavaScript execution stack there is global context at th...
Why are two different concepts both called “heap”?
...
Yes, but a heap also implies disorder and memory heaps are generally disordered. The data structure heap is extremely well ordered. So again there's an equal mismatch going the other way based on the common definition of heap.
– jmucch...
What “things” can be injected into others in Angular.js?
... more on that later) and Angular will call the provider's $get function in order to return a new instance of the service. In this case, the thing that will be injected is a function that takes a name parameter and alerts a message based on the name. We might use it like this:
app.controller('MainCo...
Webrick as production server vs. Thin or Unicorn?
...rs (Apache, Nginx, etc) can handle without spinning up Ruby*, and probably orders of magnitude faster.
* for example, if you are running behind a load balancer, you could route all rewrite traffic to a server that does not have ruby installed, and let your main servers only manage the primary traff...
Python + Django page redirect
...fox 5 'caching' 301 redirects
I had to clear my caches to change it. In order to avoid this head-scratching in the future, I was able to make it temporary like so:
from django.views.generic import RedirectView
url(r'^source$', RedirectView.as_view(permanent=False,
...
Add a prefix to all Flask routes
...prefix.
The mask argument is a `format string` formatted with, in that order:
prefix, route
'''
def newroute(route, *args, **kwargs):
'''New function to prefix the route'''
return route_function(mask.format(prefix, route), *args, **kwargs)
return newroute
Arguably, this is ...
How to use getJSON, sending data with post method?
...exOf("?") == -1 ? "?" : "&")+"callback=?", data, func, "json"); }
In order to use jsonp, and POST method, this function adds the "callback" GET parameter to the URL. This is the way to use it:
$.postJSON("http://example.com/json.php",{ id : 287 }, function (data) {
console.log(data.name);
...