当前位置：文江博客知识库 en-US 文档 Web API SVGLengthList

SVGLengthList - Web APIs 编辑

SVG length list interface

The SVGLengthList defines a list of SVGLength objects.

An SVGLengthList object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown.

Note: Starting in Gecko 5.0,the SVGLengthList DOM interface is now indexable and can be accessed like arrays

Interface overview

Also implement	None
Methods	`void clear()` `SVGLength` `initialize(in SVGLength newItem)` `SVGLength` `getItem(in unsigned long index)` `SVGLength` `insertItemBefore(in SVGLength newItem, in unsigned long index)` `SVGLength` `replaceItem(in SVGLength newItem, in unsigned long index)` `SVGLength` `removeItem(in unsigned long index)` `SVGLength` `appendItem(in SVGLength newItem)`
Properties	readonly unsigned long `numberOfItems` readonly unsigned long `length`
Normative document	SVG 1.1 (2nd Edition)

Properties

Name	Type	Description
`numberOfItems`	unsigned long	The number of items in the list.
`length`	unsigned long	The number of items in the list.

Methods

Name & Arguments	Return	Description
`clear()`	void	Clears all existing current items from the list, with the result being an empty list. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only.
`initialize(in SVGLength newItem)`	`SVGLength`	Clears all existing current items from the list and re-initializes the list to hold the single item specified by the parameter. If the inserted item is already in a list, it is removed from its previous list before it is inserted into this list. The inserted item is the item itself and not a copy. The return value is the item inserted into the list. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only.
`getItem(in unsigned long index)`	`SVGLength`	Returns the specified item from the list. The returned item is the item itself and not a copy. Any changes made to the item are immediately reflected in the list. The first item is number 0. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only.
`insertItemBefore(in SVGLength newItem, in unsigned long index)`	`SVGLength`	Inserts a new item into the list at the specified position. The first item is number 0. If `newItem` is already in a list, it is removed from its previous list before it is inserted into this list. The inserted item is the item itself and not a copy. If the item is already in this list, note that the index of the item to insert before is before the removal of the item. If the `index` is equal to 0, then the new item is inserted at the front of the list. If the index is greater than or equal to `numberOfItems`, then the new item is appended to the end of the list. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only.
`replaceItem(in SVGLength newItem, in unsigned long index)`	`SVGLength`	Replaces an existing item in the list with a new item. If `newItem` is already in a list, it is removed from its previous list before it is inserted into this list. The inserted item is the item itself and not a copy. If the item is already in this list, note that the index of the item to replace is before the removal of the item. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only. a `DOMException` with code `INDEX_SIZE_ERR` is raised if the index number is greater than or equal to `numberOfItems`.
`removeItem(in unsigned long index)`	`SVGLength`	Removes an existing item from the list. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only. a `DOMException` with code `INDEX_SIZE_ERR` is raised if the index number is greater than or equal to `numberOfItems`.
`appendItem(in SVGLength newItem)`	`SVGLength`	Inserts a new item at the end of the list. If `newItem` is already in a list, it is removed from its previous list before it is inserted into this list. The inserted item is the item itself and not a copy. Exceptions: a `DOMException` with code `NO_MODIFICATION_ALLOWED_ERR` is raised when the list corresponds to a read only attribute or when the object itself is read only.