看代码:
var file1 = "50.xsl";
var file2 = "30.doc";
getFileExtension(file1); //returns xsl
getFileExtension(file2); //returns doc
function getFileExtension(filename) {
/*TODO*/
}
看代码:
var file1 = "50.xsl";
var file2 = "30.doc";
getFileExtension(file1); //returns xsl
getFileExtension(file2); //returns doc
function getFileExtension(filename) {
/*TODO*/
}
当前回答
试试这个:
function getFileExtension(filename) {
var fileinput = document.getElementById(filename);
if (!fileinput)
return "";
var filename = fileinput.value;
if (filename.length == 0)
return "";
var dot = filename.lastIndexOf(".");
if (dot == -1)
return "";
var extension = filename.substr(dot, filename.length);
return extension;
}
其他回答
试试这个:
function getFileExtension(filename) {
var fileinput = document.getElementById(filename);
if (!fileinput)
return "";
var filename = fileinput.value;
if (filename.length == 0)
return "";
var dot = filename.lastIndexOf(".");
if (dot == -1)
return "";
var extension = filename.substr(dot, filename.length);
return extension;
}
function file_get_ext(filename)
{
return typeof filename != "undefined" ? filename.substring(filename.lastIndexOf(".")+1, filename.length).toLowerCase() : false;
}
这个简单的解决方案
function extension(filename) {
var r = /.+\.(.+)$/.exec(filename);
return r ? r[1] : null;
}
测试
/* tests */ test('cat.gif', 'gif'); test('main.c', 'c'); test('file.with.multiple.dots.zip', 'zip'); test('.htaccess', null); test('noextension.', null); test('noextension', null); test('', null); // test utility function function test(input, expect) { var result = extension(input); if (result === expect) console.log(result, input); else console.error(result, input); } function extension(filename) { var r = /.+\.(.+)$/.exec(filename); return r ? r[1] : null; }
var parts = filename.split('.');
return parts[parts.length-1];
function getFileExtension(filename)
{
var ext = /^.+\.([^.]+)$/.exec(filename);
return ext == null ? "" : ext[1];
}
测试了
"a.b" (=> "b")
"a" (=> "")
".hidden" (=> "")
"" (=> "")
null (=> "")
也
"a.b.c.d" (=> "d")
".a.b" (=> "b")
"a..b" (=> "b")