I'd use jQuery for the event triggering/AJAX and https://gist.github.com/dperini/729294 for weburl regex.
I'm not that at home on pure JavaScript AJAX calls, but is
xmlhttp.open("GET")
the right way to go at it if you want to make a POST?
Anyway the main thing you're missing is
function isUrl(url){
var regex = /^(?:(?:https?|ftp):\/\/)(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))\.?)(?::\d{2,5})?(?:[/?#]\S*)?$/i;
if(regex.test(url)){
return regex.test(url);
}else{
return regex.test("http://"+url);
}
}
So this should be your new index.html
<html>
<head>
<script>
var extensions = [".aero",".biz",".cat",".com",".coop",".edu",".gov",".info",".int",".jobs",".mil",".mobi",".museum",".name",".net",".org",".travel",".ac",".ad",".ae",".af",".ag",".ai",".al",".am",".an",".ao",".aq",".ar",".as",".at",".au",".aw",".az",".ba",".bb",".bd",".be",".bf",".bg",".bh",".bi",".bj",".bm",".bn",".bo",".br",".bs",".bt",".bv",".bw",".by",".bz",".ca",".cc",".cd",".cf",".cg",".ch",".ci",".ck",".cl",".cm",".cn",".co",".cr",".cs",".cu",".cv",".cx",".cy",".cz",".de",".dj",".dk",".dm",".do",".dz",".ec",".ee",".eg",".eh",".er",".es",".et",".eu",".fi",".fj",".fk",".fm",".fo",".fr",".ga",".gb",".gd",".ge",".gf",".gg",".gh",".gi",".gl",".gm",".gn",".gp",".gq",".gr",".gs",".gt",".gu",".gw",".gy",".hk",".hm",".hn",".hr",".ht",".hu",".id",".ie",".il",".im",".in",".io",".iq",".ir",".is",".it",".je",".jm",".jo",".jp",".ke",".kg",".kh",".ki",".km",".kn",".kp",".kr",".kw",".ky",".kz",".la",".lb",".lc",".li",".lk",".lr",".ls",".lt",".lu",".lv",".ly",".ma",".mc",".md",".mg",".mh",".mk",".ml",".mm",".mn",".mo",".mp",".mq",".mr",".ms",".mt",".mu",".mv",".mw",".mx",".my",".mz",".na",".nc",".ne",".nf",".ng",".ni",".nl",".no",".np",".nr",".nu",".nz",".om",".pa",".pe",".pf",".pg",".ph",".pk",".pl",".pm",".pn",".pr",".ps",".pt",".pw",".py",".qa",".re",".ro",".ru",".rw",".sa",".sb",".sc",".sd",".se",".sg",".sh",".si",".sj",".sk",".sl",".sm",".sn",".so",".sr",".st",".su",".sv",".sy",".sz",".tc",".td",".tf",".tg",".th",".tj",".tk",".tm",".tn",".to",".tp",".tr",".tt",".tv",".tw",".tz",".ua",".ug",".uk",".um",".us",".uy",".uz", ".va",".vc",".ve",".vg",".vi",".vn",".vu",".wf",".ws",".ye",".yt",".yu",".za",".zm",".zr",".zw"];
var delay = (function(){
var timer = 0;
return function(callback, ms){
clearTimeout (timer);
timer = setTimeout(callback, ms);
};
})();
function isUrl(url){
var regex = /^(?:(?:https?|ftp):\/\/)(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))\.?)(?::\d{2,5})?(?:[/?#]\S*)?$/i;
if(regex.test(url)){
return regex.test(url);
}else{
return regex.test("http://"+url);
}
}
function showHint(str) {
delay(function(){
str = str.toLowerCase();
var dot = str.lastIndexOf(".");
var extension = str.substr(dot);
extension = extension.split('/')[0];
var found = $.inArray(extension, extensions) > -1;
if (!isUrl(str)||!found) {
document.getElementById("txtHint").innerHTML = "";
return;
} else {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("txtHint").innerHTML = this.responseText;
}
};
xmlhttp.open("GET", "gethint.php?q=" + str, true);
xmlhttp.send();
}
}, 500)
}
</script>
</head>
<body>
<p><b>Start typing a url in the input field below:</b></p>
<form>
Url: <input type="text" onkeyup="showHint(this.value)">
</form>
<p><span id="txtHint"></span></p>
</body>
</html>
edit: Say you will start typing in http://www.example.net.. The AJAX will trigger on "http://www.example.ne" and then again when you add the last letter. To avoid that, you might try "change" instead of "keyup" event.
edit2: Now checks against list of valid domain extensions
edit3: Now waits half a second before posting the result.
edit4: Small oversight while checking for extensions, fixed with
extension = extension.split('/')[0];
Also if you want to enable users to write URL's without "http://" and similar, you'll need an edited regex or write a small hack that adds that to your string before you send it into "isUrl()".