Allow only positive and negative numbers in textbox using JavaScript regex

Question

I have a textbox called count. I want to enter only positive and negative numbers in the textbox using JavaScript or jQuery regular expression. Do not allow "text" and "decimals" and "special characters" in the textbox. Even copy and paste also it should take only positive or negative numbers.

Important:

If I copy and paste text or decimal or special character also it should not take. It should take only positive or negative numbers.
I want to enter and paste negative values without decimal.
Arrow keys should work.
Shift, Ctrl, Home, End, Enter like this buttons also should work.

Please check the following fiddle and please modify this.

Fiddle

 $(".allownumericwithoutdecimal").on("keypress keyup blur",function (event) {    
           $(this).val($(this).val().replace(/[^\d].+/, ""));
            if ((event.which < 48 || event.which > 57)) {
                event.preventDefault();
            }
        });

   
 <span>Int</span>
<input type="text" name="numeric" class='allownumericwithoutdecimal'>
<div>Numeric values only allowed  (Without Decimal Point) </div>

I am new for regex. Please help me for do this.

and "-" symbol should come only one time at the beginning. Not more than one. — sathish kumar
– sathish kumar, Commented Mar 11, 2016 at 12:38

score 1 · Accepted Answer · 2016-03-11 12:51:12Z

1

The regex you are looking for is this:

Regex: ^-?[0-9]+$

Explanation:

It checks for optional -ve sign. And only allows digits.
I have used [0-9] instead of \d because later one means numbers in different languages.

Regex101 Demo

PS: Am not a Javascript programmer so if anyone want to add fiddle or use this regex, go ahead.

edited Mar 11, 2016 at 12:51

answered Mar 11, 2016 at 12:40

user2705585

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6 Comments

sathish kumar Over a year ago

Sorry noob. Please see my points what I have mentioned. Even copy paste also it should not take. And should allow arrow keys. Can you please add this example in jsfiddle?

user2705585 Over a year ago

@sathishkumar: Well yea this is not the complete solution. It's only the regex part. Good luck with the fiddle as am not a Javascript programmer.

Wiktor Stribiżew Over a year ago

This regex is good to use on the blur event, as a final validation. Actually, a regex is basic here, the problem is the code. See my fiddle adapted a bit from my former post. No idea if it works the way you need.

user2705585 Over a year ago

@WiktorStribiżew: Thanks. I think your fiddle is what OP requires. You should post it as answer.

Wiktor Stribiżew Over a year ago

@noob: No, I do not think it is working well. I cannot paste 12345 into the field.

|

jrswgtr · Accepted Answer · 2020-11-13 12:43:33Z

1

This is also achievable without regex using Javascript keypress and charCode.

<input type="number" (keypress)="keypress($event, $event.target.value)" >

keypress(evt, value){

    if (evt.charCode >= 48 && evt.charCode <= 57 || (value=="" && evt.charCode == 45))       
    {  
        return true;
    }
    return false;
}

The given code won't allow user to enter alphabets nor decimal on runtime, just positive and negative integer values.

edited Nov 13, 2020 at 12:43

jrswgtr

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answered Nov 13, 2020 at 12:19

Farhan

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