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indexOf - how does it work?

Discussion in 'Software Development' started by Mr Red, Apr 19, 2010.

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  1. Mr Red

    Mr Red Thread Starter

    Joined:
    Dec 1, 2008
    Messages:
    76
    Hi
    I have been trying to get the index number of text in a string and indexOf seemed the most logical. And the easiest.
    but I just get a returned value of -1. I am looking for values held inside TAGs and have a solution but it annoys me that I can't get indexOf to work. When string appears to be a similar function and does work (it finds a value of 5 and alert reports the correct string).

    Code:
    function  foo(ar,n){ 
     var id = /id/g; 
     var gt = />/g; 
     var lt = /</g; 
     var kk = ar[1].toString(); 
     var kkm = kk.indexOf(id)+1; 
     var kkl = kk.search(id); 
     kkl = kkl+kk.slice(kkl).search(gt)+1; 
     var ccm =  ar[1].toString().indexOf(lt)-1; 
     var ccl =  kkl+kk.slice(kkl).search(lt); 
     alert("the first date I find  is " +kk.slice(kkl,ccl) ); 
    // non-relevant code removed
    } 
    
    Any Ideas?

    TIA
     
  2. andythepandy

    andythepandy

    Joined:
    Jul 2, 2006
    Messages:
    379
    Hi,
    The indexOf function doesn't support regular expressions. Instead you can use the search function which returns, as indexOf does, the position of the search string. Try this:
    Code:
    var id = /id/g; 
    var gt = />/g; 
    var lt = /</g; 
    var kk = "where is id?'"; 
    var kkm = kk.search(id); 
    
    alert(kkm);
    
    
    Andy
     
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