Status Response Codes
- Other domain intelligence tools:
- Domain Extractor
- FCrDNS Lookups
- IP Country Locator
- MUST
- and many more »
- This tool allows you to search for status response codes even if these are not part of IANA's Status Code Registry (IANA, 2015; Wikipedia, 2015).
- To use the tool, just submit a keyword or valid status code from 100 to 599.
- The tool is case-insensitive, so you can use lower or upper cases.
- Unlike similar tools which only match status codes, ours also match keywords.
- For instance, submitting [404], [Not Found], [Not], or [Found] returns the same record.
- If other records partially match your query, these are also returned.
- Some AJAX scripts return an http status code of 0. How could this be possible?
- A status code of 0 is not a true header response code, but the evaluation of an unsuccessful response code as a falsey value. Said evaluation is done according to a particular programming language or browser/API library. For instance, client-side (400+) or server-side (500+) status codes are classified as errors and as such can be restated as 0, a falsey value.
To illustrate, an AJAX request for an unregistered domain name should return a falsey value of 0 because no server and IP are associated to it.
Furthermore, an AJAX request for a registered domain name whose host has been removed from the Web should also return a status code of 0. The latter was observed during the Heartbleed outbreak days.
- A falsey value is something that evaluates to false according to specific programming rules (Phabricator, 2015; PHP.net, 2015a, 2015b, 2015c). For instance, in almost all programming languages 0 is a falsey value.
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As shown in the following comparative, each programming language has its own way of classifying falsey values.
JavaScriptPHP (version 5)
- false (case-insensitive)
- null (case-insensitive)
- empty string (in double or single quotes)
- 0 (as a number or string)
- 0.0 (as a float)
- empty arrays
- SimpleXML objects created from empty tags
- Furthermore, some programming languages have native functions that are shortcuts for a combination of falsey values. For instance, in PHP
isset() is a shortcut for
if(($var)&&(!$var==NULL))
while empty() is a shortcut for
if((!isset($var))||($var==false))
- Webmasters, developers, and programmers.
- IANA (2015). Hypertext Transfer Protocol (HTTP) Status Code Registry.
- Phabricator (2015). PHP Pitfalls.
- PHP.Net (2015a). Boolean Types.
- PHP.Net (2015b). PHP isset() function.
- PHP.Net (2015c). PHP empty() function.
- Wikipedia (2015). List of HTTP Status Codes.
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