Ie8 does not support indexof

The javascriptindexof method finds the first index value that can be found in the array for a given element, but indexof is not supported in IE8, this article introduces how ie8 does not support indexof. how does one browser not support indexof? you can use the following code at the beginning of scripts when writing a scripts, it allows you to use the indexOf method without local support.

If (! Array. prototype. indexOf) {Array. prototype. indexOf = function (searchElement, fromIndex) {var k; if (this = null) {throw new TypeError ('"this" is null or not defined ');} var O = Object (this); var len = O. length >>> 0; if (len = 0) {return-1;} var n = + fromIndex | 0; if (Math. abs (n) = Infinity) {n = 0;} if (n> = len) {return-1;} k = Math. max (n> = 0? N: len-Math. abs (n), 0); while (k <len) {if (k in O & O [k] = searchElement) {return k ;} k ++;} return-1 ;};}