CODEWITHSUNDEEP
javascriptjquery
MumbaiKandivali
MumbaiKandivali

Reputation: 121

Prevent repeated '+' character simultaneously on Key Up

I had regular expression which is onkeyup="this.value=this.value.replace(/[^aA0-9 +]/g,''); Which is allow string only number with '+' symbol i.e 1+2+3

I had functionality of + for combine. But in some time it allow example '+1' and also '1++3+' or '+++4+5'.

How to prevent repeated '+' and on start with '+' on keyup event so that my functionality will work.

Any suggestion. Thank You.

Upvotes: 1

Views: 203

Answers (2)

Sumesh TG
Sumesh TG

Reputation: 2575

var element=document.getElementById("txtSum");
element.addEventListener('keyup', function() {
  this.value = this.value
    .replace(/\s/g, '') // Removes space
    .replace(/^\++/g, '') // Remove begining with +
    .replace(/[^aA\d +]/g,'') 
    .replace(/\++/g, '+'); // Replace multiple +
   
});
<input type="text" id="txtSum"/>

Upvotes: 1

CertainPerformance
CertainPerformance

Reputation: 371029

Attach the event listener properly using Javascript, and then you can replace multiple pluses in a row with a single plus by matching \++ (literal plus, repeated) and replacing with +. Also note that 0-9 in a character set reduces to \d, which is a bit nicer to read:

element.addEventListener('keyup', function() {
  this.value = this.value
    .replace(/[^aA\d +]/g,'')
    .replace(/\++/g, '+');
});

You might also want to check for spaces around pluses so as to avoid, for example, a+ +a. If that's the case, then you can use:

.replace(/ *\+[ +]/g, ' + ')

That will replace optional spaces, followed by a plus, followed by any combination of pluses and spaces, with a single plus surrounded by a space on each side. (of course, you could also replace with a plus alone, without spaces, if you wanted)

Upvotes: 1

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