问(JS_console)当点击按钮时，为什么这个循环会中断？

EN

var animal = new Array(); //Declare Array 

animal[0] = 'cat';
animal[1] = 'dog';
animal[2] = 'cow';
animal[3] = 'snake';
animal[4] = 'goat';
animal[5] = 'tiger';
animal[6] = 'lion';
animal[7] = 'horse';


var createFunc = function(i){
    return function(){
        var token_field = document.getElementById('animal_name'); 
        token_field.value = animal[i]; //Change the value of the field with each array value

        var path_field = document.getElementById('To_do');
        path_field.value='feed'; // Change the other field with 'feed'

        var submit_all = document.getElementById('graph_submit');
        submit_all.click(); //submit the form
    };
};
for (var i = 0; token.length > i; i++) {
    setTimeout(createFunc(i), 2000);
}