validate natural input number with ngpattern

Question

I use ng-pattern=\"/0-9/\" to set price_field do not accept decimal number. But when I input natural number (from 0 to 9999999),

Answer 1

Mobile Number(*)

Phone is required.

the following code will help for phone number validation and the respected directive is

app.directive('validatePhone', function() {
var PHONE_REGEXP = /^[789]\d{9}$/;
  return {
    link: function(scope, elm) {
      elm.on("keyup",function(){
            var isMatchRegex = PHONE_REGEXP.test(elm.val());
            if( isMatchRegex&& elm.hasClass('warning') || elm.val() == ''){
              elm.removeClass('warning');
            }else if(isMatchRegex == false && !elm.hasClass('warning')){
              elm.addClass('warning');
            }
      });
    }
  }
});