防止用户多次刷新页面

Question

I am facing a issue when a user holds F5 for 10-15 minutes the web page becomes unresponsive and finally IIS throws an error.

To manage this, I want to restrict the user from pressing F5(lock F5 event) after certain number of times. After some time interval say 5 minutes I want to enable the refresh functionality(unlock F5 event).

I am using a cookie to save the number of times user presses F5. To handle cookie I am using the code mentioned here .

Assign a event to check if F5 keypress.

$(document).on("keydown", tryingF5);

I am using a variable to hold the cookie value and incrementing it once user presses F5.

var numberOfF5Click = 1;
var thresholdClick = 10;
var numberOfF5Click = 1;
function tryingF5(e) {
        if ((e.which || e.keyCode) == 116) {
            //alert(numberOfF5Click);
            if (numberOfF5Click > thresholdClick) {
                e.preventDefault();
                alert("Multiple refresh has been prevented for some time!!");
            }

            numberOfF5Click = numberOfF5Click + 1;
            docCookies.setItem("NumberOfF5Click", numberOfF5Click);

            //alert("F5 Clicked =" + numberOfF5Click);
        };
    };

The complete code is setup here : JSBin

Question: The code is not working as expected, something is n and How could I do it better ?

Answer 1

Try this:

var everyXMinutes = 5 * 1000; // 5 seconds
var maxPerEveryXMinutes = 5; // 5 times per x seconds.

document.onkeydown = function (e) {
    if (e.keyCode === 116) {
        if (!localStorage.refreshments) {
            localStorage.refreshments = JSON.stringify([]);
        }
        var refreshments = JSON.parse(localStorage.refreshments);
        var date = new Date();
        if (date.getTime() - refreshments[refreshments.length - 1] >= everyXMinutes) {
            refreshments = [];
        } else if (refreshments.length >= maxPerEveryXMinutes) {
            alert("You must wait " + ((everyXMinutes - (date.getTime() - refreshments[refreshments.length - 1])) / 1000) + "s in order to be able to use the refresh function.");
            return false;
        }            
        refreshments.push(date.getTime());
        localStorage.refreshments = JSON.stringify(refreshments);
    }
};