The given code checks if a string is blank or not. However, it is incomplete as it only contains a function definition and does not have any implementation. Here's a complete version of the code that checks if a string is blank or not:
```javascript
function isblank(s) {
for (var i = 0; i < s.length; i++) {
if (s[i] !== ' ') {
return false;
}
}
return true;
}
```
You can use this function to check if a string is blank or not. For example:
```javascript
console.log(isblank("")); // true
console.log(isblank(" ")); // false
console.log(isblank("Hello")); // false
console.log(isblank(" ")); // false
console.log(isblank("A B C")); // false
```
