The GlideElement class is not generally instantiated on its own, but it is used for elements in a GlideRecord object, and provides methods for interacting with them. An element generally refers to a data column in the record, such as the number field on a task record, or the sys_updated_on field of a record. You can access a GlideElement from a server-side GlideRecord object (for example, by using gr.number), or by using the getElement method of a GlideRecord object.

Best practice dictates that you always use the getter and setter functions: getValue(), and setValue() if you want to get the value of the field. Directly accessing the server-side GlideElement property however, will give you a reference to the GlideElement object.

Let's say for example, that we have a table with a column called short_description. When we query this table, we get a GlideRecord object populated with various properties. Each field in the table becomes a property in the GlideRecord object, but those properties are not just strings and numbers and other basic/primitive data types. Instead, each property corresponding to a field in the table/records is an object that is an instance of the GlideElement class.

That means that this field/property, gr.short_description, corresponds to a GlideElement object, with all of the methods you'll see next (and more; we're just going to cover the most useful ones here that developers are likely to use on a relatively frequent basis).

But this isn't without implications; perhaps you've heard JavaScript referred to as a loosely typed language. This isn't a colloquial term; it actually means that the data types in JavaScript are fluid. In many other languages, when you declare a variable and initialize it, you intrinsically link it to a given data type: string, integer, float, boolean, and so on. However, in JavaScript, you can declare a var, set it to a string value, and then later modify its value so it contains a number, and so on.

This is useful in some situations; for example, you set the value of the short_description field with a line of code such as gr.short_description = 'New short description.";. However, this can actually be a bad thing, since you're overwriting the GlideElement object that used to be in the parent GlideElement object's short_description property. Using the GlideRecord's setValue() method, however, correctly sets the value within the GlideElement object.