jQuery Checkbox is true if Textbox has value of 0 but false if the Textbox is blank [duplicate]

Question

I have this function where if the textbox has a value of 0 the checkbox will be set to true. But I have this weird scenario where if the textbox is blank or greater than 0 I need the checkbox to be false

When I debug true this seems to be "" and 0 are the same thing Does anyone know how I would go about making this work?

$(document).on('blur change keyup', '.CostInput', function () {
  if ($(this).val() == 0) {
    $('input#Enquiry_Cost_InputFree_0').prop('checked', true);
  }

  if ($(this).val() > 0 || "") {
    $('input#Enquiry_Cost_InputFree_0').prop('checked', false);
  }
});

And I have created a JS fiddle = https://jsfiddle.net/barrycorrigan/Lqxuvr4w/9/

Answer 1

There is a difference between == and === in JavaScript.

0 == ""  // => true
0 === "" // => false

You probably mean to say:

$(document).on('blur change keyup', '.CostInput', function () {
  let val = $(this).val();

  if (+val === 0) {
    $('input#Enquiry_Cost_InputFree_0').prop('checked', true);
  }

  if (+val > 0 || val === "") {
    $('input#Enquiry_Cost_InputFree_0').prop('checked', false);
  }
});

For more information on how it works, see here: https://stackoverflow.com/a/359509/9741277