JavaScript函数陷入循环

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.

Answer 1

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.