Source for demo by Kyle Simpson. See also description.
a="D=docume;C,hi=[],d,j,k=31,1,e=25,,g,l,m=[0,0,5,4,4];;g=cubs(f,e (! match(/\\/|\\\\/)l=Y=RegExp(g/([.*+?|$^\\(\\)[\\]{}])/\\\\$1 ,'g ) ; (((Z=m[e])&&l>=Z)||l>=3&&(b=Sin fromCharCode(a++)) !b)) ;else b=0;bi.unsh t(b+g Y b=;coinue} f>=c -1-e e>2;e--;coinue} }}f++/\"/g)&&(b=Sin fromCharCode(a++)) !b)) ;else b=0;bi.unsh t(b+'\\\\\"' /\"/g)}}j='\"'+/\\\\/\\\\\\\\ /\"/\\\\\"'\";for(b in \"'+i.join(\"/\"\"plit(\"/\"))aRegExp(c[b][0],\"g\"),c[b]ubs(1) eval(a)';return((j <d )?j:d)}T(with(DD.gebgetElemeById;d=gebid('q .value,h=C)qld phplh }}Ireturn'<p><textarea '+d+'></textarea><input '+d+'l>b'}D.body.innerHTML+=I('q'<p><button onclick=\"T()\">V</button>'+I('p' ";for(b in c=" ')/ g./ if/ );/tr/.s/,b/a=/c=/){/(d/nt/id=/)+'/g,'/f=0/}if(/var / break/ ){if(/ .length/;gebid('/c.match(/').value=/.replace(/function /c.replace(/while(a<=k/if(a==10||a==13)a++".split("/"))a=a.replace(RegExp(c[b][0],"g"),c[b].substr(1));eval(a)