Three practical methods for JS to determine whether there are duplicate values ​​in an array_javascript skills

Method 1:

Copy code The code is as follows:

var ary = new Array("111" ,"22","33","111");

var s = ary.join(",") ",";

for(var i=0;i< ary.length;i ) {

if(s.replace(ary[i] ",","").indexOf(ary[i] ",")>-1) {

alert("There are duplicate elements in the array: " ary[i]);

break;Foreign Language House

}

}

Method 2:

Copy code The code is as follows:

var ary = new Array(" 111","22","33","111");

var nary=ary.sort();

for(var i=0;i
if (nary[i]==nary[i 1]){

alert("Array duplicate content: " nary[i]);

}

}

Method three: Inland transportation

Copy code Code As follows:

function isRepeat(arr){

var hash = {};

for(var i in arr) {

if (hash[arr[i]])

return true;

hash[arr[i]] = true;

}

return false;

}