Home  >  Article  >  Web Front-end  >  JavaScript Array object extends indexOf() method_javascript tips

JavaScript Array object extends indexOf() method_javascript tips

WBOY
WBOYOriginal
2016-05-16 16:49:071646browse

Background: Among the standard methods of Array objects in JavaScript, there is no indexOf() method, which can be extended through the following code.

Copy code The code is as follows:

if (!Array.prototype.indexOf) {
Array.prototype.indexOf = function(elt) {
var len = this.length >>> 0;
var from = Number(arguments[1]) || 0;
from = (from < 0) ? Math.ceil(from) : Math.floor(from);
if (from < 0) from = len;
for (; from < len; from ) {
if (from in this && this[from] === elt) return from;
}
return - 1;
};
}
Statement:
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn