The <filter> tag is normally used to define an SVG filter. The <filter> tag has a required id attribute which identifies which filter will be applied to the which graphic.

The <filter> tag must be nested within <defs> tag. The <defs> tag is short for definitions and it allows definition of special element such as filter.

Copy the following code into Notepad and save the file as "filter.svg". Place the file in your Web directory only:

• The id attribute of the <filter> tag defines a unique name for the filter (the same filter can be used in many elements in the document)

• The filter:url( i.e,#Gaussian_Blur) property is used to link an element to a filter. The # character must be used when linking to the filters id

• The filter effects is defined with the <feGaussianBlur> tag. The fe prefix is used for all filter.

• The stdDeviation attribute of the <feGaussianBlur> tag define the amount of the blur

• The in="SourceGraphic" part defines that the effect is created from the whole image itself

Let's take another example with a different stdDeviation: