help trying to make a variable out of part of a string

[yabai]

hi. i am new to javascript and am asking if someone can point me to a good resource or let me know what terms I should be searching for.

I have a site with a page that uses javascript to take the url, checks it and then writes out a new one.

<script type="text/javascript"> 
var str = document.URL; 
//start from doc_library rather than doc_number 
var startdocnr = str.indexOf("&doc_library="); 
//alert (startdocnr); 
var enddocnr = str.indexOf("&year="); 
//alert (enddocnr); 
var docnr = str.substring(startdocnr,enddocnr); 
//alert(docnr); 
document.write ('<a href="http://domain.co.uk/1?func=direct' + docnr + '">'); </script>

This is the url

http://domain.co.uk/1&func=item-global&doc_library=abc01&doc_number=003764840&year=&volume=&sub_library=

I would like to amend the javascript so that it will work if i come from a different url which doesn't have &year=&volume=&sub_library= in the url

Therefore i think I need to work out some code that makes the variable 'docnr' by finding the string 'doc_number=' and then the next 9 digits. What is this type of task called in javascript. Any pointers or examples would be much appreciated.

Thanks.

[Philip M]

Try this:-

var str = "http://domain.co.uk/1&func=item-global&doc_library=abc01&doc_number=003764840"
var docnr =  str.match(/doc_number=\d{9}/);
alert (docnr);

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