Question

I need a Javascript which will validate an input field, allowing only numbers and 1 comma in it, and maximum 8 digits.

How can this be done doing javascript?

Like using it on the input fields KeyUp?

Hope someone can help me out.

Answer 1

var inputfield = document.getElementById("ID of input");
var commalocation;
var commas = 0;
var signs = 0;
var nums = 0;
var chars = inputfield.value;
chars = chars.split("");
for (var i = 0; i < chars.length; i++){
  if (chars[i] == ','){
    commas++;
    commalocation = i;
  }else if (chars[i] >= '0' && chars[i] <= '9'){
    nums++;
  }else{
    signs++;
  }
}
if (nums > 8 || commas > 1 || signs > 0 || commalocation == 0 || commalocation == chars.length - 1){
  inputfield.value = "";
}else{
  var inputvalue = inputfield.value;
}