Need help to improve this largest common substring implementation
I have scanned the web for largest substring implementations to use in my xmlhttp request, however I found that only 1 has worked, in other cases the responsetext hasn't been treated as a string no matter what I have written:
txt = txt + ""; // or
txt = new string(txt);)
This function works, but it is terrible slow. I am just wondering if you code gurus out there could help me improve this algorithm.
The site that I'm calling a xmlhttprequest is looking like this
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<title>Index of /</title>
</head>
<body>
<h1>Index of /</h1>
<ul><li><a href="/"> Parent Directory</a></li>
<li><a href="random"> random/</a></li>
<li><a href="random_2/"> random_1/</a></li>
<li><a href="radnfdom"> random/</a></li>
<li><a href="rasrdndddom_1/"> random_1/</a></li>
<li><a href="random_43"> random/</a></li>
<li><a href="test/"> random_1/</a></li>
</ul>
</body></html>
In other words you can strip of all the html tags for better speed, I will just search for the plain text in the html text document.
You can watch the script in action here at tdsoft.se
<html>
<head>
<script type="text/javascript">
var txt;
var buildName = "";
var xmlhttp;
function lcs(a, b) {
var aSub = a.substr(0, a.length-1);
var bSub = b.substr(0, b.length-1);
if (a.length == 0 || b.length == 0) {
return "";
} else if (a.charAt(a.length-1) == b.charAt(b.length-1)) {
return lcs(aSub, bSub) + a.charAt(a.length-1);
} else {
var x = lcs(a, bSub);
var y = lcs(aSub, b);
return (x.length > y.length) ? x : y;
}
}
function loadXMLDoc(url,cfunc)
开发者_开发百科{
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=cfunc;
xmlhttp.open("GET",url,true);
xmlhttp.send();
}
function myFunction()
{
loadXMLDoc("http://tdsoft.se/testni.html",handleXML);
}
var checkState = function(xmlhttp, callback) {
try{
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
callback();
}
else {
// Check back again 1 sec later
setTimeout(checkState, 1000);
}
}
catch(err){
setTimeout(checkState, 1000);
}
};
function handleXML()
{
checkState(xmlhttp, function() {
txt=xmlhttp.responseText;
buildName = "random";
txt = txt.replace(/<[^>]*>/g, "");
var myvar = "";
myvar = lcs(txt, "random");
document.write(myvar);
});
}
</script>
</head>
<body onLoad="myFunction()">
</body>
</html>
Seems like you would want to take a different approach at this.
I'm not exactly sure the point of what you are trying to do but it seems like something like this would be what you want:
- You request a Document
- Parse the links in the document and store them in an object keyed by their ids with values being their text
- Change your lookup function to go after the link list
Here's a code example (using jQuery for simplicity):
//untested!
var links = {};
function successFunction(data) {
var aTags = data.find('a');
aTags.each(function() {
var $this = $(this);
links[$this.attr('href')] = $this.text();
});
}
function lookup(id) {
return links[id] || '';
}
$.ajax({
url: 'requestPage.htm',
success: successFunction
});
EDIT:
If you want to do this non-jquery you can just replace the following things:
$.ajaxto your XMLHttpRequest methoddata.find('a')togetElementsByTagName.each(function(){...})tovar i = aTags.length; while(i--) { links[aTags[i].href] = aTags[i].innerHTML; }
加载中,请稍侯......
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