copias o codigo do ficheiro JS a que queres faz isso colas e depois selecionas bas62 encode e shrink variables apanhei aqui um ficheiro JS do forum o theme.js ele fica assim :
eval(function(p,a,c,k,e,r){e=function(c){return(c<a?'':e(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--)r[e(c)]=k[c]||e(c);k=[function(e){return r[e]}];e=function(){return'\\w+'};c=1};while(c--)if(k[c])p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c]);return p}('6 A(){2 a=3.j(\'W\');k(2 i=a.l-1;i>=0;i--){4(B&&a[i].o<C)a[i].5.m=(a[i].o+C)+\'D\';E 4(F&&(a[i].G>a[i].p||a[i].p==0))a[i].5.H=\'X\';E 4(\'q\'8 a[i]&&a[i].q.H==\'r\'&&(a[i].q.m==\'\'||a[i].q.m==\'r\')&&(a[i].G>a[i].p||a[i].p==0)&&(a[i].o!=0))a[i].5.m=(a[i].o+Y)+\'D\'}}4((Z&&!10)||B||F)I(A);6 J(){2 a=3.j(\'11\');k(n 8 a){4(a[n].7==12||a[n].7.K(\'13 14\')==-1)15;a[n].5.16=\'17\';a[n].18=6(){9.5.L=9.5.m=9.5.L==\'r\'?19:\'r\'}}}I(J);6 1a(a,b,c){2 d=3.1b(a);2 e=d.j(\'w\');4(e.l>0){2 f=e[e.l-1];f.7=f.7.x(/\\s*M/,\'1c\')}2 g=d.j(\'1d\')[0];2 h=3.1e(\'1f\');1g(h,\'<a 1h="\'+c.1i+\'" \'+(\'N\'8 c?c.N:\'\')+\'><w 1j="M"\'+(\'O\'8 c?\' 1k="\'+c.O+\'"\':\'\')+\'>\'+c.1l+\'</w></a>\');g.1m(h)}2 P=6(){2 a,1n;k(2 b=0;b<3.t.l;b++)k(2 c=0;c<3.t[b].Q.l;c++){u=3.t[b].Q[c];4(u.R.K(\'v:S\')!=-1){T=u.R.x(/v:S/1o,\'v.y\');3.t[b].1p(T,u.5.1q)}}2 d=3.j(\'v\');k(z 8 d){d[z].1r=6(){9.7+=\' y\'};d[z].1s=6(){9.7=9.7.x(1t 1u(\' y\\\\b\'),\'\')}}}4(1v&&\'U\'8 V)V.U(\'1w\',P);',62,95,'||var|document|if|style|function|className|in|this||||||||||getElementsByTagName|for|length|height|oImage|offsetHeight|clientWidth|currentStyle|auto||styleSheets|oCssRule|LI|span|replace|iehover|oListItem|smf_codeBoxFix|is_webkit|20|px|else|is_ff|scrollWidth|overflow|addLoadEvent|smc_toggleImageDimensions|indexOf|width|last|sCustom|sId|smf_addListItemHoverEvents|rules|selectorText|hover|sNewSelector|attachEvent|window|code|scroll|24|is_ie|is_ie4|IMG|undefined|bbc_img|resized|continue|cursor|pointer|onclick|null|smf_addButton|getElementById|position_holder|ul|createElement|li|setInnerHTML|href|sUrl|class|id|sText|appendChild|newSelector|gi|addRule|cssText|onmouseover|onmouseout|new|RegExp|is_ie7down|onload'.split('|'),0,{})) a mim parece-me bem confuso, eu nao o consigo ler..