Keep input value after refresh page

EDIT: Keep value of more inputs

HTML:

<input type="text" id="txt_1" onkeyup='saveValue(this);'/> 
<input type="text" id="txt_2" onkeyup='saveValue(this);'/> 

Javascript:

<script type="text/javascript">
        document.getElementById("txt_1").value = getSavedValue("txt_1");    // set the value to this input
        document.getElementById("txt_2").value = getSavedValue("txt_2");   // set the value to this input
        /* Here you can add more inputs to set value. if it's saved */

        //Save the value function - save it to localStorage as (ID, VALUE)
        function saveValue(e){
            var id = e.id;  // get the sender's id to save it . 
            var val = e.value; // get the value. 
            localStorage.setItem(id, val);// Every time user writing something, the localStorage's value will override . 
        }

        //get the saved value function - return the value of "v" from localStorage. 
        function getSavedValue  (v){
            if (!localStorage.getItem(v)) {
                return "";// You can change this to your defualt value. 
            }
            return localStorage.getItem(v);
        }
</script>