if and else tags (Control Tag)

The if else tag has a one mandatory attribute 'test'

test: 
Its type is boolean.
It acceptes the multiple conmbinations of the conditions which must be evalue to true or false.

Example
<s:if test="student.marks > 80"> A grade</s:if> 
<s:elseif test="student.marks > 70"> B grade</s:elseif> 
<s:elseif test="student.marks > 50"> C grade</s:elseif> 
<s:elseif test="student.marks > 35"> D grade</s:elseif> 
<s:else> Failed </s:else>

Here student object will be available into the valuestack.