Comparing two input fields

Question

I have this function which i am using to compare two input fields. If the user enters the same number in both the text field. On submit there will be an error. Now i would like to know if there is a way to allow same number but not higher than or lower the value of the previous text box by 1. For example if user enters 5 in previous text box, the user can only input either 4, 5 or 6 in the other input field.Please give me some suggestions.

   <script type="text/javascript">
function Validate(objForm) {
var arrNames=new Array("text1", "text2");
var arrValues=new Array();
for (var i=0; i<arrNames.length; i++) {
var curValue = objForm.elements[arrNames[i]].value;
if (arrValues[curValue + 2]) {
alert("can't have duplicate!");
return false;
}
arrValues[curValue] = arrNames[i];
}
return true;
}
</script>

<form onsubmit="return Validate(this);">
<input type="text" name="text1" /><input type="text" name="text2" /><button type="submit">Submit</button>
</form>

What would you try? Also, I don't think your currenct function really checks for duplicate values. — Bergi
– Bergi, Commented Aug 21, 2012 at 15:20

Nathaniel Flick · Accepted Answer · 2019-11-18 01:42:58Z

11

A tidy way to do it which is easy to read:

var firstInput = document.getElementById("first").value;
var secondInput = document.getElementById("second").value;

if (firstInput === secondInput) {
    // do something here if inputs are same
} else if (firstInput > secondInput) {
    // do something if the first input is greater than the second
} else {
    // do something if the first input is less than the second
}

This allows you to use the values again after comparison as variables (firstInput), (secondInput).

edited Nov 18, 2019 at 1:42

Nathaniel Flick

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answered Aug 21, 2012 at 15:29

Lemex

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2 Comments

Darren Over a year ago

Do something if Second is greather than Second? I think you mean if firstInput < secondInput or not equal?

Shailendra Madda Over a year ago

@LmC I need to check firstInput > secondInput but it only validating for 1st digit only how to fix it? Ex: 59>9 here it only checking 5>9

su- · Accepted Answer · 2012-08-21 15:55:21Z

3

Here's a suggestion/hint

if (Math.abs(v1 - v2) <= 1) {
    alert("can't have duplicate!");
    return false;
}

And here's the jsfiddle link, if you want to see the answer

edited Aug 21, 2012 at 15:55

answered Aug 21, 2012 at 15:25

su-

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5 Comments

Shailendra Madda Over a year ago

@I pm I need to check firstInput > secondInput but it only validating for 1st digit only how to fix it?

su- Over a year ago

You can do something like this in your validate function: if (('' + a)[0] <= ('' + b[0])) { alert('invalid'); return false; } Basically ('' + anyNumber)[0] will get you the first digit of a number.

Shailendra Madda Over a year ago

@I pm Thank you for quick response..I didn't get you Once see my code here I wanna validate firstInput > secondInput I used this document.getElementById('noOfWorkingComputers').value > document.getElementById('noOfComputers').value but taking only validating for 1st digit only how to fix it? Ex: 59>9 here it only checking 5>9

Shailendra Madda Over a year ago

here it's working fine for only single digit..If it checking like string even that single digit also not gonna be work naa?

su- Over a year ago

Could you post a jsfiddle (or something similar) link? So it would be easier to look at your problem.

Zeke Nierenberg · Accepted Answer · 2012-08-21 15:21:36Z

1

Give them both IDs.

Then use the

if(document.getElementById("first").value == document.getElementById("second").value){
    //they are the same, do stuff for the same
}else if(document.getElementById("first").value >= document.getElementById("second").value
    //first is more than second
}

and so on.

answered Aug 21, 2012 at 15:21

Zeke Nierenberg

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