fix abc to abs

examples/js/nodes/math/Math1Node.js

@@ -30,7 +30,7 @@ THREE.Math1Node.TAN = 'tan';
 THREE.Math1Node.ASIN = 'asin';
 THREE.Math1Node.ACOS = 'acos';
 THREE.Math1Node.ARCTAN = 'atan';
-THREE.Math1Node.ABS = 'abc';
+THREE.Math1Node.ABS = 'abs';
 THREE.Math1Node.SIGN = 'sign';
 THREE.Math1Node.LENGTH = 'length';
 THREE.Math1Node.NEGATE = 'negate';