<script type="text/javascript">

function d2h(d) {

return d.toString(16)

}

function h2d(d) {

return parseInt(d, 16)

}

function dot2num(d) {

var n = d.split(".");

return 256 * (256 * (256 * +n[0] + +n[1]) + +n[2]) + +n[3]

}

function num2dot(d) {

for (var n = d % 256, t = 3; t > 0; t--)d = Math.floor(d / 256), n = d % 256 + "." + n;

return n

}

function convert() {

var d = document.getElementById("ipnum").value, n = /^(\d|[01]?\d\d|2[0-4]\d|25[0-5])\.(\d|[01]?\d\d|2[0-4]\d|25[0-5])\.(\d|[01]?\d\d|2[0-4]\d|25[0-5])\.(\d|[01]?\d\d|2[0-4]\d|25[0-5])$/, t = /^\d+$/;

d.match(n) ? d = dot2num(d) : d.match(t) && 4294967296 > +d && (d = num2dot(d)), document.getElementById("ipnum").value = d

}

</script>