Changes

 <!--define variable containing birth date provided by user. For Example: 14 अगस्त 1907-->{{#vardefine:birthdate|14 अगस्त{{{जन्म|}}}}}<!--Calculate length of the birthdate string-->

<!--If the last 4 characters are really birth year then these should be numeric. Check this.-->{{#ifeq:{{#expr:{{#var:birthyear}}/{{#var:birthyear}}}}|1|{{#vardefine:yearIsNumeric|1}}}} |{{#ifexprvardefine:yearIsNumeric|0}}}}<!--If birth year is numric -then extract rest of the characters as birth day (i.e. 14 अगस्त in the example we are taking)-->{{#varifeq:birthdatelength}}>4) and ({{#var:yearIsNumeric}}==|1)|{{#vardefine:birthday|{{#sub:{{#var:birthdate}}|0|{{#expr:{{#var:birthdatelength}}-4}}}}}}

<!--If birth year is not numeric -assign the entire string provided by the user as birth day. For example: 14 अगस्त--> '''जन्मतिथि{{#ifeq:''' {{#var:yearIsNumeric}}|0|{{#vardefine:birthday|{{#var:birthdate}}}}}}<br!--Assign category for birthday-->'''जन्मवर्ष{{#ifeq:''' {{#var:birthyearyearIsNumeric}}|0|[[Category:जन्मतिथि: {{#var:birthday}}]]}}<br!--Assign category for birth year-->