如何在特定文件上调用JavaScript函数?

var handleFileSelect;
handleFileSelect=function(e){
    n=new FileReader;
    n.onload=function(e){
    localStorage.settings = e.target.result
    },
    n.readAsText(this.files[0])
},

document.getElementById("settings_file").addEventListener("change",handleFileSelect,!1);
var handleFileSelect;
handleFileSelect=function