Leetcode - per page performance calculator

perfcal.js

const ppc=function(){
var total_problems=window.document.getElementsByClassName("reactable-data");
var i;
var sum=0;
var total=total_problems[0].childNodes.length;
for (i=0;i<total;i++){
  var row=total_problems[0].childNodes[i];
  var td=row.childNodes[0];
  var attribute=td.getAttribute("value");
  if(attribute==="ac"){
    sum=sum+1;
  }
}
console.log(sum+"/"+total+" :: Solve rate = "+((sum/total)*100)+"%");
};