Look for partial name of cookie using Javascript -

on website use cookie show or hide content. depending on how users log in determine content visible them. i.e. if log in facebook, site looks cookie called "fbsr_3324". problem second part of cookie name changes every user (fbsr_2889 fbsr_9902 etc). therefore want know if can , suggest how can check first part of cookie name (i.e. existance of cookies starting fbsr_

here current current javascript use:

function checkcookie() {     contentdiv=document.getelementbyid("cookiefb");     if (document.cookie.indexof("fbsr_")!=-1) {         contentdiv.style.display="none";     }     else {         contentdiv.style.display="block";     } } 

the code you're using perform if logged in using facebook, if had cookie set containing value 'fbsr_haha, gotcha'
perhaps job regex:

/^|;\s*fbsr_[0-9]{4}\=[^;]+;/.test(document.cookie); 

should trick.
expression explanation:

• ^|;: either start of string, or semi-colon
• \s*: followed 0 or more spacces
• fbsr_[0-9]{4}: matches fsbr_ , sequence of 4 numbers
• \=: write =, need escape = (lookarounds), best escape once not enough
• [^;]+ semi-colon at least once or more
• ;: literal semi-colon

where use expression:

function checkcookie() {     contentdiv=document.getelementbyid("cookiefb");     if (/^|;\s*fbsr_[0-9]{4}\=[^;]+;/.test(document.cookie))     {//facebooker!         contentdiv.style.display="none";         return;//return here, can leve else out     }     contentdiv.style.display="block"; } 

well, should it.
however, can't myself, if ever more familiar js, , feel optimizing of scripts, consider this:

var checkcookie = (function(expr) {     var contentdiv = document.getelementbyid('cookiefb');     return function()     {         contentdiv.style.display="block";         if (expr.test(document.cookie))         {             contentdiv.style.display="none";         }     }; }(/^|;\s*fbsr_[0-9]{4}\=[^;]+;/)); 

this optimized version of exact same code have. atm, code query dom element id cookiefb every time called, , it'll create instance of regexp, too. using closure, can query dom once, , create instance of regexp once, , re-use each call.
it's bit more efficient, , micro-optimization in case, couldn't myself ;)