function IsInt() { var chCode = ('charCode' in event) ? event.charCode : event.keyCode; if (chCode >= 48 && chCode <= 57) { return true; } else { alert('Numbers only'); return false; } } var classname = document.getElementsByClassName("IsInt"); for(var i=0;i<classname.length;i++){ classname[i].onkeypress=function() {return IsInt();}; }
<a href='http://z54.com'>Example of how to create reuseable JavaScript Class Libraries - Data Validation: Is Integer</a><Br> <input type='text' class='IsInt' />