var cache = [];

cache[0] = 0;

cache[1] = 1;

cache[2] = 2;

cache[3] = 3;

cache[4] = 4;

cache[r] = r;

console.log(cache.length);

for(key in cache){

    if(isNaN(key))continue;

    else cache.splice(key,1); // cache.splice(key) is working fine, ***

}

console.log(cache);

Question : in line *** Why splice(key) is working fine (Deleting All Elements with Numeric Index) and splice(key,1) not working fine (Not Deleting Elements with Numeric index). Even i have tried

splice(key,1) // Not working as splice(key)

splice(key--,1) // Even not working as splice(key)

splice(key,0) // not deleting any thing

You can copy and paste code in Firebug console for testing.