java script checks two input values only by digit

Question

var tbv = document.getElementById("inputFrom");
var tbb = document.getElementById("inputTo");
var submit_check = document.getElementById("checkValues");


function blr() {
  var von = tbv.value;
  var bis = tbb.value;

  console.log(von);
  console.log(bis);

  if (von >= bis || bis <= von) {
    checkValues.disabled = true;
  } else {
    checkValues.disabled = false;
  }

}
tbv.addEventListener("blur", blr);
tbb.addEventListener("blur", blr);

From: <br>
<input type="text" class="form-control" pattern="(|-)?[0-9]{0,3}?" title="Min: -100" id="inputFrom" />
<br> To: <br>
<input type="number" class="form-control" pattern="(|-)?[0-9]{0,3}?" title="Max: 300" id="inputTo" />
<br>
<button type="submit" class="btn btn-primary" id="checkValues"> Check </button>

As I explained above, I want to check if the value of the input "From" is greater or equal to the input "To".

The thing is, this works only by checking digit for digit, so that if input "From" has the value 12 and input "To" has the value 1, it is correct.

Anyone an idea what I´m doing wrong?

An <input> value is a String, which means the values are being compared lexically, rather than numerically; you need to first convert to a Number to compare values as numbers: parseInt(von, 10), parseFloat(von), +von, Number(von) (and probably many other ways). — David Thomas
– David Thomas, Commented Apr 7, 2017 at 12:42

Abhisek Malakar · Accepted Answer · 2017-04-07 13:00:41Z

1

Try this

function blr() {
var von = parseint(tbv.value);
var bis = parseint(tbb.value);

console.log(von);
console.log(bis);

if (von >= bis) {
 checkValues.disabled = true;
} else {
  checkValues.disabled = false;
}

}
tbv.addEventListener("blur", blr);
tbb.addEventListener("blur", blr);

I have jsut parse the input as Integer and then compare, and there is no need to compare in both direction like a>=b and b<=a .-silly

edited Apr 7, 2017 at 13:00

answered Apr 7, 2017 at 12:45

Abhisek Malakar

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1 Comment

Pugazh Over a year ago

Please check the spellings!!

Pugazh · Accepted Answer · 2017-04-07 12:55:59Z

By default .value returns a string, so use parseInt() to parse the value into a number.

Note: von >= bis and bis <= von means the same. Use of any one is enough.

var tbv = document.getElementById("inputFrom");
var tbb = document.getElementById("inputTo");
var submit_check = document.getElementById("checkValues");


function blr() {
  var von = parseInt(tbv.value);
  var bis = parseInt(tbb.value);

  console.log(von);
  console.log(bis);

  if (von >= bis) {
    checkValues.disabled = true;
  } else {
    checkValues.disabled = false;
  }

}
tbv.addEventListener("blur", blr);
tbb.addEventListener("blur", blr);

From: <br>
<input type="text" class="form-control" pattern="(|-)?[0-9]{0,3}?" title="Min: -100" id="inputFrom" />
<br> To: <br>
<input type="number" class="form-control" pattern="(|-)?[0-9]{0,3}?" title="Max: 300" id="inputTo" />
<br>
<button type="submit" class="btn btn-primary" id="checkValues"> Check </button>

Bardo · Accepted Answer · 2017-04-07 12:45:03Z

0

Javascript is loosely typed. It's variables get their type when data is loaded the first time, but can change type during their lifetime.

When you create a variable and load it with data from an input, it's considered a string, and string comparison is made character by character, not as a whole.

If you convert your values to int or float, using parseInt() or parseFloat() you'll have your problem solved.

answered Apr 7, 2017 at 12:45

Bardo

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Comments

Sam Tolton · Accepted Answer · 2017-04-07 12:46:03Z

0

Well for a start you don't need the OR part of this - (von >= bis || bis <= von) - you can just use (von >= bis).

If the values are always going to be numeric, then you can simply cast them by putting a plus before them, like so:

if (+von >= +bis) {
    checkValues.disabled = true;
} else {
    checkValues.disabled = false;
}

answered Apr 7, 2017 at 12:46

Sam Tolton

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Comments

Tushar Gupta · Accepted Answer · 2017-04-07 12:49:51Z

Use parseInt(). Since you get the value of textbox as string, you need to convert the string to number

var tbv = document.getElementById("inputFrom");
var tbb = document.getElementById("inputTo");
var submit_check = document.getElementById("checkValues");


function blr() {
  var von = parseInt(tbv.value);
  var bis = parseInt(tbb.value);

  console.log(von);
  console.log(bis);

  if (von >= bis) {
    checkValues.disabled = true;
  } else {
    checkValues.disabled = false;
  }

}
tbv.addEventListener("blur", blr);
tbb.addEventListener("blur", blr);

From: <br>
<input type="text" class="form-control" pattern="(|-)?[0-9]{0,3}?" title="Min: -100" id="inputFrom" />
<br> To: <br>
<input type="number" class="form-control" pattern="(|-)?[0-9]{0,3}?" title="Max: 300" id="inputTo" />
<br>
<button type="submit" class="btn btn-primary" id="checkValues"> Check </button>

Alvin · Accepted Answer · 2017-06-23 19:35:15Z

0

Agree with David Thomas. You need to convert string to a number. Since you already have regular expression on your input box try using Number object to convert your string literal to Number and then compare.

function blr() {
  var von = Number(tbv.value);
  var bis = Number(tbb.value);

  console.log(von);
  console.log(bis);

  if (von >= bis) {
    checkValues.disabled = true;
  } else {
    checkValues.disabled = false;
  }

}

For more detail on Number object visit this link

edited Jun 23, 2017 at 19:35

answered Apr 7, 2017 at 13:00

Alvin

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