javascript - Detecting if inputs match by having common elements -

i have 2 input boxes , trying compare them, in order see if have common elements. reason, though, not working. code:

html:

personal address line 1: <input type = "text" id = "persadd1" /> address line 1: <input type = "text" id = "addline1" /> <input type = "submit" value = "continue" onclick = "vali()" /> 

javascript:

function vali() {     var add1str = document.getelementbyid('persadd1').value;     var add2str = document.getelementbyid('addline1').value;     var arr1 = add1str.split(" ");     var arr2 = add2str.split(" ");     var arr3 = [];     (var = 0; < arr1.length; i++) {         (var j = 0; j < arr2.length; j++) {             if (arr1[i] === arr2[j]) {                 arr3.push( arr1[i] );                 if(arr3 !== ""){                     alert("error");                 }             }         }     } } 

jsfiddle

any ideas?

the below work you.

function vali() {     var add1str = document.getelementbyid('persadd1').value;     var add2str = document.getelementbyid('addline1').value;     var arr1 = add1str.split(" ");     var arr2 = add2str.split(" ");     var arr3 = [];     (var = 0; < arr1.length; i++) {         (var j = 0; j < arr2.length; j++) {             if (arr1[i] === arr2[j]) {                 arr3.push(arr1[i]);                 //console.log(arr3);             }         }     }     if (arr3.length > 0) { //check if array 3 has items, if yes alert error.         alert("error");     } } 

demo