function alertSize() {
  var myWidth = 0, myHeight = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    myWidth = window.innerWidth;
    myHeight = window.innerHeight;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    myWidth = document.documentElement.clientWidth;
    myHeight = document.documentElement.clientHeight;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    myWidth = document.body.clientWidth;
    myHeight = document.body.clientHeight;
  }
}

function tabEnter(field) {
    var keyCode = event.keyCode ? event.keyCode : event.which ? event.which : event.charCode;

    if (keyCode == 13) {
        document.getElementById(field).focus();
        return false;
    } else {
        if ((keyCode != 13)) {
            return true;
        }
    }
}

function numericOnly(field) {
    var keyCode = event.keyCode ? event.keyCode : event.which ? event.which : event.charCode;

    if (keyCode <= 47 || keyCode >= 59)
        return false;
}