html - Array index doesn't go out of bound in Javascript -


i creating javascript application want generate arrayindexoutofbound exception. have created array of size 5 , trying insert elements fibonacci series it. ideally, should throw exception after inserting 6th element, not throwing exception. please check code , let me know views. attached code , screenshots of output.

<!doctype html> <html>  <head>     <title>error handling demo</title>     <script type="text/javascript">      var = 1;     var fibona = [];     fibona.length=5;          function generatenext()         {                if(i>1)                 {                     number1.value = number2.value;                     number2.value = number3.value;                 }              number3.value = parseint(number1.value) + parseint(number2.value);             i++;              fibona.push({'num1':number1.value, 'num2':number2.value, 'num3':number3.value});         }      </script> </head>  <body>     <h1>fibonacci series game</h1>      <p>         number 1 :         <input type = "number" name = "number1" value = 0 id = "num1">     </p>      <p>         number 2 :         <input type = "number" name = "number2" value = 1 id = "num2">     </p>      <p>         next number :         <input type = "number" name = "number3" id = "num3">     </p>      <p>         <input type = "button" name = "generatenext" value = "generate next number" onclick = "generatenext()">     </p>  </body>  </html>

enter image description here

what experiencing normal behavior of push method.

the push() method adds new items end of array, , returns new length.

note: new item(s) added @ end of array.

note: method changes length of array.

please read more here http://www.w3schools.com/jsref/jsref_push.asp

update: if want able constraint max length of array, simplest way constant variable setting holding length of array , checking value array's length. if still wanna throw exception when/if index greater max value, can throwing exception throw 'your exception message'


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