Answer by Nishanth for convert HTML code to Javascript variable (string)

Method 1 Remove the line breaks, making the entire string a single line

var lines = '<div id="jwplayer"><center>...</center></div>';
document.write(lines);

Method 2 Escape the line breaks with backslashes.

var lines = '<div id="jwplayer">\
    <center>\
      ...\
    </center>\
  </div>';
document.write(lines);

Method 3: Concatenate the string a line at a time

var lines = '<div id="jwplayer">';
lines += '<center>';
lines += '...';
lines += '</center>';
lines += '</div>';
document.write(lines);

Method 4 : Create an array strings and join them

var lines = [
  '<div id="jwplayer">',
  '<center>',
  '...',
  '</center>',
  '</div>'].join(' ');
document.write(lines);

Source : Javascript document.write('HTML CODE HERE') and using a var grabbed by flash