The following table shows which Unicode characters are treated as whitespace in browsers and per spec. Hex | IE8 Firefox WebKit Opera ECMA262/Unicode 5.10 ------+---------------------------------------------------- 9 | 9 9 9 9 9 a | 10 10 10 10 10 b | 11 11 11 11 11 c | 12 12 12 12 12 d | 13 13 13 13 13 20 | 32 32 32 32 32 85 | 133 133 a0 | 160 160 160 160 1680 | 5760 5760 5760 180e | 6158 6158 2000 | 8192 8192 8192 8192 2001 | 8193 8193 8193 8193 2002 | 8194 8194 8194 8194 2003 | 8195 8195 8195 8195 2004 | 8196 8196 8196 8196 2005 | 8197 8197 8197 8197 2006 | 8198 8198 8198 8198 2007 | 8199 8199 8199 8199 2008 | 8200 8200 8200 8200 2009 | 8201 8201 8201 8201 200a | 8202 8202 8202 8202 200b | 8203 8203 2028 | 8232 8232 8232 8232 2029 | 8233 8233 8233 8233 202f | 8239 8239 8239 205f | 8287 8287 3000 | 12288 12288 12288 12288 feff | 65279 65279 fffe | 65534 Test case: http://software.hixie.ch/utilities/js/live-dom-viewer/?%3Cscript%3E%0D%0Afor%20(var%20i%20%3D%201%3B%20i%20%3C%200xFFFF%3B%20%2B%2Bi)%0D%0Atry%20%7B%0D%0A%20eval(%22var%22%20%2B%20String.fromCharCode(i)%20%2B%20%22x%22%20%2B%20i%20%2B%20%22%3D%5C%22%5C%22%3Bw(x%22%20%2B%20i%20%2B%20%22%2B%22%20%2B%20i%20%2B%20%22)%22)%0D%0A%7D%20catch(e)%20%7B%0D%0A%7D%0D%0A%3C%2Fscript%3E