Update 645-language-elseif.markdown

Author: Joe7M

_build/reference/645-language-elseif.markdown

@@ -2,6 +2,30 @@
 
 > ELSEIF
 
-foo = 2: if foo==1: ? "one": ELSEIF foo==2: ? "two": fi
+Alternative condition in an IF statement.
+
+### Example 1
+
+~~~
+foo = 2
+if foo == 1
+  print "one"
+ELSEIF foo == 2
+  print "two"
+endif
+~~~
+
+### Example 2: using IF ... ELSE ... IF instead of ELSEIF
+
+~~~
+foo = 2
+if foo == 1
+  print "one"
+else
+  if foo == 2
+    print "two"
+  endif
+endif
+~~~