单选题Which XSL if statement checks for the existence of a homepage attribute within an STS Universal User XML structure?（）A <xsl:if test=//stsuuser:AttributeList/stsuuser:Attribute[attr='homepage']>B <xsl:if test=//stsuuser:AttributeList/stsuuser:Attribute[
题目
单选题
Which XSL if statement checks for the existence of a homepage attribute within an STS Universal User XML structure?（）
A
<xsl:if test=//stsuuser:AttributeList/stsuuser:Attribute[attr='homepage']>
B
<xsl:if test=//stsuuser:AttributeList/stsuuser:Attribute[@name='homepage']>
C
<xsl:if-exists=//stsuuser:AttributeList/stsuuser:Attribute/custom:Homepage>
D
<xsl:if-exists=//stsuuser:AttributeList/stsuuser:Attribute[@name='homepage'])>