Svg filter effect use

<svg width="100%" height="100%" version="1.1">
	<!--  Filter body  -->
	<defs>
		<filter id="Gaussian_Blur">
			<!-- feGaussianBlur  There are many kinds of filter effects   More can go w3c in svg seek  stdDeviation  The degree of filter use   It's just like skin grinding   The higher the value, the stronger the effect -->
			<feGaussianBlur stdDeviation="5" />
		</filter>
	</defs>
	<!--  Use  filter:url(# Filter filter Of Id) That is to say  -->
	<!--  Use  filter:url(#Gaussian_Blur) -->
	<circle cx="100" cy="50" r="40" stroke="black" stroke-width="2" fill="green"  style="filter:url(#Gaussian_Blur)" />
</svg>