Input number validation - Restrict to enter only numbers or digits, int & float both

Question

How to restrict the input field to enter only numbers/digits int and float both. Sometimes we need to allow both integer as well as float value for fields like amount, so in

Answer 1

No need for the long code for number input restriction just try this code.

It also accepts valid int & float both values.

Javascript Approach

onload =function(){ 
  var ele = document.querySelectorAll('.number-only')[0];
  ele.onkeypress = function(e) {
     if(isNaN(this.value+""+String.fromCharCode(e.charCode)))
        return false;
  }
  ele.onpaste = function(e){
     e.preventDefault();
  }
}

 Input box that accepts only valid int and float values.

jQuery Approach

$(function(){

  $('.number-only').keypress(function(e) {
	if(isNaN(this.value+""+String.fromCharCode(e.charCode))) return false;
  })
  .on("cut copy paste",function(e){
	e.preventDefault();
  });

});

 Input box that accepts only valid int and float values.

UPDATE

The above answers are for most common use case - validating input as a number.

But as per comments, some wants to allow few special cases like negative numbers & showing the invalid keystrokes to user before removing it, so below is the code snippet for such special use cases.

$(function(){
      
  $('.number-only').keyup(function(e) {
        if(this.value!='-')
          while(isNaN(this.value))
            this.value = this.value.split('').reverse().join('').replace(/[\D]/i,'')
                                   .split('').reverse().join('');
    })
    .on("cut copy paste",function(e){
    	e.preventDefault();
    });

});

 Input box that accepts only valid int and float values.