Truncate string in JavaScript

I have a url as string in javascript like follows :

http://localhos开发者_JS百科t:8080/Blah.ff?param=1&param=2...

I want to filter the string and get

?param=1&param=2....

How can I do this in javascript?

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var str= "http://localhost:8080/Blah.ff?param=1&param=2";
var str2 = str.substr(str.indexOf("?"), str.length);
alert(str2);

http://jsfiddle.net/praveen_prasad/a9XBe/1/

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var urlstring = "http://localhost:8080/Blah.ff?param=1&param=2";
var querystring = '?' + urlstring.split('?')[1];

http://jsfiddle.net/ipr101/htUa3/

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There are a lot of ways to do this. I would start with the window.location or location.href elements. Read up some more here:

http://www.w3schools.com/js/