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<field> (JavaScript)

  • Article

Specifies documentation information, including a description, for either a field or member that's defined on an object.

<field name="fieldName" static="true|false" type="FieldType" integer="true|false" domElement="true|false" mayBeNull="true|false" elementType="ArrayElementType" elementInteger="true|false" elementDomElement="true|false" elementMayBeNull="true|false" helpKeyword="keyword" locid="descriptionID" value="code">description</field>

Parameters

  • name
    The name of the field or member. When the <field> element is used in a constructor function, name is required and defines the member to which the tag applies. When the <field> element is directly annotating a field, this attribute is ignored, and the name used by Visual Studio is the name of the actual field in the source code.

  • static
    Optional. Specifies whether the field is a member of the constructor function or a member of the object returned by the constructor function. Set to true to treat the field as a member of the constructor function. Set to false to treat the field as a member of the object returned by the constructor function.

  • type
    Optional. The data type of the field. The type can be one of the following:

    • An ECMAScript language type in the ECMAScript 5 specification, such as Number and Object.

    • A DOM object, such as HTMLElement, Window, and Document.

    • A JavaScript constructor function.

  • integer
    Optional. If type is Number, specifies whether the field is an integer. Set to true to indicate that the field is an integer; otherwise, set to false. This attribute is not used by Visual Studio to provide IntelliSense information.

  • domElement
    Optional. This attribute is deprecated; the type attribute takes precedence over this attribute. This attribute specifies whether the documented field is a DOM element. Set to true to specify that the field is a DOM element; otherwise, set to false. If the type attribute is not set and domElement is set to true, IntelliSense treats the documented field as an HTMLElement when performing statement completion.

  • mayBeNull
    Optional. Specifies whether the documented field can be set to null. Set to true to indicate that the field can be set to null; otherwise, set to false. The default value is false. This attribute is not used by Visual Studio to provide IntelliSense information.

  • elementType
    Optional. If type is Array, this attribute specifies the type of the elements in the array.

  • elementInteger
    Optional. If type is Array and elementType is Number, this attribute specifies whether the elements in the array are integers. Set to true to indicate that the elements in the array are integers; otherwise, set to false. This attribute is not used by Visual Studio to provide IntelliSense information.

  • elementDomElement
    Optional. This attribute is deprecated; the elementType attribute takes precedence over this attribute. If type is Array, this attribute specifies whether the elements in the array are DOM elements. Set to true to specify that the elements are DOM elements; otherwise, set to false. If the elementType attribute is not set and elementDomElement is set to true, IntelliSense treats each element in the array as an HTMLElement when performing statement completion.

  • elementMayBeNull
    Optional. If type is Array, specifies whether the elements in the array can be set to null. Set to true to indicate that the elements in the array can be set to null; otherwise, set to false. The default value is false. This attribute is not used by Visual Studio to provide IntelliSense information.

  • helpKeyword
    Optional. The keyword for F1 help.

  • locid
    Optional. The identifier for localization information about the field. The identifier is either a member ID or it corresponds to the name attribute value in a message bundle defined by OpenAjax metadata. The identifier type depends on the format specified in the <loc> (JavaScript) tag.

  • value
    Optional. Specifies code that should be evaluated for use by IntelliSense instead of the function code itself. For <field>, this attribute is supported for constructor functions, but is not supported for object literals. You can use this attribute is to provide type information when the field type is undefined. For example, you can use value=’1’ to treat the field type as a number.

  • description
    Optional. A description for the field.

Remarks

The name attribute is required when you're documenting a field in a constructor function. For all other scenarios, all attributes for the <field> element are optional.

When you're documenting a constructor function, the <field> element must appear immediately before the field declaration. The name attribute must match the field name that's used in the source code. For object members, the name attribute can be omitted if the <field> element appears immediately before the object member declaration.

Example

The following code example shows how to use the <field> element.

// Use of <field> in an object definition.
var Rectangle = {
    /// <field type = 'Number'>The width of the rectangle.</field>
    wid: 5,
    /// <field type = 'Number'>The length of the rectangle.</field>
    len: 0,
    /// <field type='Number'>Returns the area of the rectangle.</field>
    getArea: function (wid, len) {
        return len * wid;
    }
}

// Use of <field> in a constructor function.
// The name attribute is required.
function Engine() {
    /// <field name='HorsePower' type='Number'>The engine's horsepower.</field>
    this.HorsePower = 150;
}

The following example shows how to use the <field> element with the static attribute set to true.

function Engine() {
    /// <field name='HorsePower' static='true' type='Number'>static field desc.</field>
}

Engine.HorsePower = 140;
// IntelliSense on the field is available here.
Engine.

The following example shows how to use the <field> element with the static attribute set to false.

function Engine() {
    /// <field name='HorsePower' static='false' type='Number'>Non-static field desc.</field>
}

Engine.HorsePower = 140;
var eng = new Engine();
// IntelliSense on the field is available here.
eng.

The following example shows how to use the <field> element with the value attribute.

function calculator(a) {
    /// <field name='f' value='1'/>
}
new calculator().f.   // Completion list for a Number.

See Also

Concepts

XML Documentation Comments (JavaScript)