Why doesn't indexOf work on an array IE8?
The below function works fine on Opera, Firefox and Chrome. However, in IE8 it fails on the if ( allowed.indexOf(ext[1]) == -1) part.
Does anyone know why? Is there any obvious mistake?
function CheckMe() {
var allowed = new Array('docx','xls','xlsx', 'mp3', 'mp4', '3gp', 'sis', 'sisx', 'mp3', 'wav', 'mid', 'amr', 'jpg', 'gif', 'png', 'jpeg', 'txt', 'pdf', 'doc', 'rtf', 'thm', 'rar', 'zip', 'htm', 'html', 'css', 'swf', 'jar', 'nth', 'aac', 'cab', 'wgz');
var fileinput=document.getElementById('f');
var ext = fileinput.value.toLowerCase().split('.');
if ( allowed.indexOf(ext[1]) == -1)
{
document.getElementById('uploadsec').innerHTML = document.getElementById('uploadsec').innerHTML;
alert('This file type is not allowed!');
}
}
Versions of IE before IE9 don't have an .indexOf() function for Array, to define the exact spec version, run this before trying to use it:
if (!Array.prototype.indexOf)
{
Array.prototype.indexOf = function(elt /*, from*/)
{
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;
};
}
This is the version from MDN, used in Firefox/SpiderMonkey. In other cases such as IE, it'll add .indexOf() in the case it's missing... basically IE8 or below at this point.
如果你使用jQuery，你可以使用$ .inArray（）来代替。
If you're using jQuery and want to keep using indexOf without worrying about compatibility issues, you can do this :
if (!Array.prototype.indexOf) {
Array.prototype.indexOf = function(val) {
return jQuery.inArray(val, this);
};
}
This is helpful when you want to keep using indexOf but provide a fallback when it's not available.