SOURCE

function getNum(str){
    var arr=str.split("")
    var obj={}
    arr.forEach(i=>{
        if(obj[i]){
            obj[i]++
        }else{
            obj[i]=1
        }
    })
    var max=0
    var s=""
    for(let j in obj){
        if(obj[j]>max){
            max=obj[j]
            s=j
        }
    }
    console.log(s,max)
}
getNum("abdgdbcaethbganmugthaesqszaphfdvwd")