Make a function only run once (Javascript)

This is an old question but I was brought here because I needed something similar. To anyone who comes next time, here was what I eventually did:
I simply declared a variable with an initial count of 0. Then every time my function runs, it auto increases. The code I want to run once just checks if the count is 1, then it runs. If not, it doesnt. Like this:

let count = 0;
count === 1 ? doSomething : doNothing
count++

Does it help?

Try this, I have defined isFunctionCalled:Boolean variable for handle it.

var isFunctionCalled = false;

function submitForm() {
  $('#inputForm').submit;
  if ($("#inputValue").val() != inputException) {

    if (!isFunctionCalled) {
      charSetName();
    }

    $("#inputValue").val("");
  }
  $("#inputValue").val("");
}

function charSetName() {
  var nameSet = false;
  if (nameSet == false) {
    nameSet = true;
    charDetails[0] = $("#inputValue").val();
    document.getElementById("name").innerHTML = "<li id='name''>Name: " + charDetails[0] + "</li>";
  }

  isFunctionCalled = true;
}

Mind the executed variable:

var something = (function() {
    var executed = false;
    return function () {
        if (!executed) {
            executed = true;
            // do something
        }
    };
})();

There are a lot of ways to do this.

Just a simple way is to set a flag value.

if(flag){
//your code here...
flag = !flag;
}

SO, if the value of the flag is 1 at first it will work. Then as the flag value is changed to 0, then the next time it is called, it will not be invoked, as flag is 0.