Find value in String and delete it an everything else after it

Question

If I have a string which could be either

index.php?value1=123&value2=xyz

or

index.php?value2=xyz

how would I remove &value2=xyz or ?value2=xyz if value2 exists in the string?

xyz will be random each time whereas the name value2 will rename constant but the length of xyz will always be the same

Answer 1

Perhaps the simplest approach is:

var valueToKeep = value.split(/[&?]value2/)[0];

Note that this will remove everything after the &value2 or ?value2 part. As an alternative, I would propose the following, which will remove the value2=... part, even if it occurs mid-url:

var valueToKeep = value.replace(/value2[^&]*&?/, "");

http://jsfiddle.net/LTH7j/1/