Creating user interfaces in JavaScript can sometimes lead to a problem, especially when the interface used AJAX to load data from the server. As many actions will be event driven by the user you can find that when a user triggers lots of events all at once the browser will send out lots of AJAX requests all at once. This can easily cause bandwidth issues but can also lead to the user getting confused while they patiently await the browser to settle down and let them get on with things.

The for loop in JavaScript can be used to iterate through all items in an array or properties of an object. This makes looping through any object or array very easy. As in the following example that printing out all items in an array.

Here is a function to create a group of radio buttons in a HTML form. The three parameters are:

MySQL uses the datatype TINYINT to store boolean values. MySQL stores the value as TINYINT(1) which is the same as a bit so the value is either 0 (false) or 1 (true). Using boolean fields can be very useful, but it can be costly in processing as to change the value you have to query the database, find out the value of the field and then act accordingly.

Here is a simple MySQL query that can be used to toggle the value already present in the TINYINT field without having to do any pre-querying.

It is very easy to break a program with a simple typo. Instead of typing == when comparing two values you type = and actually assign a variable. This is an easy way to introduce a bug as you will not always notice it until your program doesn't work. There is an easy way of avoiding this.

By using the following syntax:

Here are a few of the built in JavaScript functions available.

To get the length of a string use the length variable. This returns the number of characters in a string.

var str = 'abcdef';
str.length; // returns 6

The charAt function will return the character at the point specified in the parameter. So to get the first character of a string use: