need to return true or false based on if value in text field is a specific number

Question

I am looking to return true if the user entered 4 into the input field.

function validateAddition() {
  if($("#validateAddition").val() == 4) {
    return true;
  } else {
    return false;
  }
}

<input value="" 
class="validate[required,onlyNumber,length[0,1]funcCall[validateAddition]] text-input" 
type="text" id="validateAddition" name="validateAddition" />

Added this into the english language js file:

"validateAddition":{
    "nname":"validateAddition",
    "alertText":"* Your math is off, try again."}

This should be fine, let me know what you think is wrong.

Answer 1

http://www.w3schools.com/jsref/jsref_parseInt.asp

return (parseInt($('#validateAddition').val()) == 4)

EDIT: MooGoo is correct, I was mistaken as far as my explanation.

However is idea of using +val is probably not the best. While the method above WILL work as you require a much better solution would be as follows:

if(($('#validateAddition').val()-0) == 4)

The reason we want to -0 as opposed to +0 is simply because if it is a string and you want to perform any additional operations incase it is, you will no longer have the original string.

Answer 2

If you want to allow other characters as well and return true only if the text of input field contains 4, you should do like this instead:

if($("#validateAddition").val().indexOf('4') != -1) {

Answer 3

It would make sence to compare the value to a string, since the value is a string. That allows you to use strict equals avoiding unnecessary automatic conversions. Also you can simplify the function.

function validateAddition() {
  return $("#validateAddition").val() === "4";
}

Answer 4

You can put your validation in the language file, looking something like this

"validateAddition": {
    "regex": /[0-3]|[5-9]/,//something that matches on all numbers but four
    "alertText": "* Your math is off, try again."
},