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<param> (JavaScript)

Specifies documentation information for a parameter in a function or method.

<param name="parameterName" type="ParameterType" integer="true|false" domElement="true|false" mayBeNull="true|false" elementType="ArrayElementType" elementInteger="true|false" elementDomElement="true|false" elementMayBeNull="true|false" locid="descriptionID" parameterArray="true|false" optional="true|false" value="code">description</param>
name

Required. The name of the parameter.

type

Optional. The data type of the parameter. 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 parameter is an integer. Set to true to indicate that the parameter 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 parameter is a DOM element. Set to true to specify that the parameter 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 parameter as an HTMLElement when performing statement completion.

mayBeNull

Optional. Specifies whether the documented parameter can be set to null. Set to true to indicate that the parameter 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.

locid

Optional. The identifier for localization information about the parameter. 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) element.

parameterArray

Optional. Specifies whether the documented parameter can be repeated in the function call, similar to repeating parameters supported in the String.format function. Set to true to indicate that the parameter can be repeated; otherwise, set to false. This attribute is not used by Visual Studio to provide IntelliSense information.

optional

Optional. Specifies whether the documented parameter is optional in the calling function. Set to true to indicate that the parameter is optional; otherwise, set to false.

value

Optional. Specifies code that should be evaluated for use by IntelliSense instead of the function code itself. You can use this attribute is to provide type information when the parameter type is undefined. For example, you can use value=’1’ to treat the parameter type as a number.

description

Optional. A description of the parameter.

The only required attribute is name. All other attributes are optional.

Elements used to annotate functions, such as <summary> (JavaScript), <param> (JavaScript), and <returns> (JavaScript), must be placed in the function body before any statements.

If there are multiple <param> elements that have the same name, one of the <param> elements is used and the redundant elements are ignored. The behavior that determines which element is used is not defined. If name refers to a nonexistent parameter, the element is ignored.

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

function areaFunction(radiusParam)
{
    /// <summary>Determines the area of a circle when provided a radius parameter.</summary>
    /// <param name="radius" type="Number">The radius of the circle.</param>
    /// <returns type="Number">The area.</returns>
    var areaVal;
    areaVal = Math.PI * radiusParam * radiusParam;
    return areaVal;
}

// Uses of <param> with the value attribute.

function calculate(a) {
    /// <param name='a' value='1'/>
    a.    // Completion list for a Number.
}

function calculate(a) {
    /// <param name='a' value='{x:0,y:0}'/>
    a.    // x and y appear in the completion list.
}
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