JavaScript has member functions for all objects, such as “valueOf” and “toString”. When you use literal numbers, Booleans, strings, undefined and null are different from the counterparts that you use for objects. This example shows this: There are ways that you can implicitly convert an object into a literal number, boolean or string. You can…
The JavaScript Object is very versatile and useful. It works a little like the Object base type in Java and the associative array type like %hash from Perl, dict from Python or array from PHP, and is the best of both worlds. You can also use them for String to Object mapping. You can initialize…
JavaScript is easy to write but can be difficult to debug effectively due to the limited debugging functionality it provides. One big difficulty is the lack of an effective display of debugging messages. You can overcome these limitations with the help of external debuggers. If you are developing JavaScript code for the Firefox browser, then…
Unlike most other programming languages, you can use both undefined and null values in JavaScript. This can confuse someone who comes to JavaScript from another programming language. When an object is undefined, it means that it still has to be declared or has been declared and not given a value. Null is a special value…
Assertion is a technique you can use to debug JavaScript code. You use assertion to ensure that an expression evaluates to true during script execution. This means that if any expression evaluates to false, there is possibly a bug in your code. There is no inbuilt assert function in JavaScript, but it is simple to…
It is common to want to join several smaller strings into a large string. The obvious way to do this is with a string concatenation operation, but in JavaScript, this can have a negative effect on performance. This is because the string concatenation operations can produce too many intermediate strings, making it perform poorly. As…
The most popular open-source database engine in the world, MySQL is a powerful database engine known for its high performance, reliability and ease of use. Many large internet companies use MySQL to power their databases and applications based on the LAMP stack (Linux, Apache, MySQL, PHP/Perl/Python). MySQL is platform-independent and runs on more than 20…
Security is an essential consideration for any computer system and MySQL is no exception to this rule. One big security problem that administrators can often overlook is obsolete accounts. These accounts were created for people who no longer use them and are big security holes waiting to be found. The user table stores user accounts,…
On a standard MySQL installation, remote access is disabled by default. This is great if you are sitting next to your server but generally inconvenient if you are not. With the advent of modern support teams spanning the globe, it is entirely possible to administer a server that is in a different country or continent…
It does not matter what data is stored in your database, you want to prevent unauthorized access. If the data is not secure, then anyone with the time and motivation can potentially access it over the internet. Once they are in your database, they can take all your data or delete it if they want….
