LastIndexOf not working in Internet Explorer

Question

I have the following code:

var currentServerlist = []; var newServerIp = document.getElementById('add_server').value; if( CurrentServerIP != newServerIp ) { $('#failoverServers td.row_selector').each(function() { var row = $(this).closest('tr'); var serverIp = row.find('td[rel=ip]').text(); currentServerlist.push(serverIp); }); if(currentServerlist.lastIndexOf(newServerIp) != -1) { return true; } return false; } 

But I found that lastIndexOf does not work in InternetExplorer (it works in Chrome).

How can i fix this?

Answer 1

According to the ES5 compatibility table, Array.prototype.lastIndexOf supported in all browsers except IE8 and below.

If you need to support such browsers, you can use one of the available poly-regiments (or more, the full ES5 polyfill solution ).

Answer 2

Some browsers (IE) do not support many JavaScript properties. Usually I find a solution on mdn:

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/lastIndexOf

The code is there:

 if (!Array.prototype.lastIndexOf) { Array.prototype.lastIndexOf = function(searchElement /*, fromIndex*/) { "use strict"; if (this == null) throw new TypeError(); var t = Object(this); var len = t.length >>> 0; if (len === 0) return -1; var n = len; if (arguments.length > 1) { n = Number(arguments[1]); if (n != n) n = 0; else if (n != 0 && n != (1 / 0) && n != -(1 / 0)) n = (n > 0 || -1) * Math.floor(Math.abs(n)); } var k = n >= 0 ? Math.min(n, len - 1) : len - Math.abs(n); for (; k >= 0; k--) { if (k in t && t[k] === searchElement) return k; } return -1; }; } 

Answer 3

lastIndexOf seems to be implemented only in IE9 / 10. You need to use a gasket to support it. See: ES5-shim , line 509-535 in particular.