Javascript function going into a loop

Question

I have this below function in my project:-

function RowSelection() {
  var table = document.getElementById("tbl_Audit");
  if (table != null) {
    for (var x = 0; x < table.rows.length; x++) {
      for (var j = 0; j < table.rows[x].cells.length; j++) {
        if (j = 4) {
          alert("condition passed " + j)
          table.rows[x].cells[j].onclick = function() {
            tableText(this);
          }
        }
      }
    }
  }
}

when this function is triggered it goes into a never ending loop. Can anybody please help me identify what I am doing wrong here.

Console log the table.rows.length; What's the count ? And also table.rows[x].cells.length whats the count ? — Nandan Bhat
– Nandan Bhat, Commented Oct 28, 2016 at 22:26

nnnnnn · Accepted Answer · 2016-10-28 22:27:39Z

4

Change if (j=4) to if (j===4).

= is an assignment, which isn't a syntax error so the code runs, but it changes the value of j to 4, so (assuming 4 is less than the number of cells) your loop condition will always be true.

answered Oct 28, 2016 at 22:27

nnnnnn

150k30 gold badges210 silver badges247 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Nandan Bhat Over a year ago

Hmm, that's right. But can that cause never ending loop ?

nnnnnn Over a year ago

@Nandan - Sure, because j is the inner loop's counter.

Nandan Bhat Over a year ago

Okay, But what I thought was, for every iteration, the if block should be executed right? So if the table.rows[x].cells.length value is 1000 (just example) it should show alert for 1000*outer loop count. Isn't it ?

nnnnnn Over a year ago

@Nandan - At the end of every iteration of the inner loop, j will be incremented by the j++ of the for, but then the if (j=4) will change j back to 4. So every time (after the first) that the inner loop condition is evaluated j will be 5. If that is less than table.rows[x].cells.length then the inner loop condition will always be true.

Collectives™ on Stack Overflow

Javascript function going into a loop

1 Answer 1

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related