Question

I have three cases:

1) when the string looks like this /televisions?3dtv=true – I need to remove ?3dtv=true from it

2) when the string looks like this /televisions?3dtv=true&brand=panasonic – I need to remove &brand=panasonic from it

3) when the string looks like this /televisions?3dtv=true&brand=panasonic&led=true – I need to remove everything after last & including & so – &led=true

I guess number 2 and 3 are the same.

Any help would be appreciated.

Answer 1

Unfortunately, lastIndexOf is only supported in IE9, so alternatively you can consider regular expressions:

var href = $(obj).next().attr('href').replace(/(?:&[^&]*|\?[^?]*)$/, '');

I updated the answer accordingly to the new requirements. The expression will either replace everything from the last & on or, if there is none, from ?. As the alternation is evaluated from left to right, it is guaranteed that &... is replaced if it is present.

Expression explained:

/                 # start expression
  (?:             # open non-capturing group
      &           # match & literally
      [^&]*       # match any character but & as often as possible
      |           # OR
      \?          # match ? literally
      [^?]*       # match any character but ? as often as possible
  )               # close group
  $               # match the end of the string
/                 # end expression