x=''+self 

j=''

'd1d7a1712345691a7512d427b1da7d9ab7519a4b721a961721d694'

.split``

.map(_=>j+=`x[0x${_}]+`)

console.log(eval(j+'""'))

x=''+self 

// becomes "[object Window]"

j='' 

// initialize `j` which will be javascript to pass to `eval`

'd1d7a17123456...' 

// this is a list of index values to 

// look up in `x` in hexidecimal so that each 

// index is a single character

.split``

// split the index values into an array `[0xe, 0x2 ...`

.map(_=>j+=`x[0x${_}]+`)

// map over the index values and write a string like

// this `x[0xe]+x[0x2]+...` into `j`

console.log(eval(j+'""'))

// evaluate `j` with an empty string at the end

// `x[0xe]+x[0x2]+""` and log it out

document.body.innerHTML += 'click anywhere...'

onclick = () =>

  document.body.style.background = 

    `#${Math.random().toString(16).substr(-6)}`

Math.random() // random number between 0 and 1

.toString(16) // convert to hex string (something like "0.2d6bcee4198d4")

.substr(-6) // grab the last 6 characters

const instructionsEl = document.createElement('p');

instructionsEl.innerHTML = 'click anywhere...';

document.body.appendChild(instructionsEl);

const randomHexColor = () => 

  `#${Math.random().toString(16).substr(-6)}`;

document.addEventListener('click', () => {

  document.body.style.background = randomHexColor();

});