Prepare for screenshot

function prepareForScreenshot(selector) {
		var textElements = document.querySelectorAll(selector);
    for (i = 0; i < textElements.length; ++i) {
    		textElements[i].innerHTML = randomiseString(textElements[i].textContent);
    }
    
    var imgElements = document.querySelectorAll('img');
    for (i = 0; i < imgElements.length; ++i) {
    		imgElements[i].style.filter = 'blur(7px)';
    }
    
}

function randomiseString(str){
    var chars = "  abcdefghijklmnopqrstuvwxyz0123456789";
    var _str = str.replace(/[^-]/g,function(a){
        return chars[Math.floor(Math.random() * chars.length)];
    });
    return _str;
}

prepareForScreenshot('span');