while_loop_firstname

var name = "John Doe";

function getFirstName (fullName){
    var i=0;
    var firstName ="";
    var next = fullName[0];
    var length=fullName.length;
    while(i<length && next!==" "){
        firstName+=fullName[i];
        i++;
        next=fullName[i];
    }
    console.log( firstName);
}

getFirstName(name);