====== mouseDown ======
Emulates pressing of the left mouse button in the current coordinates of the cursor on the page.
===== Syntax =====
<code javascript>mouseDown = function();</code>

===== Examples =====
  -<code javascript>loadURI('google.ru');
//Obtain a random element with tag "input"
var element = getElement('input');
//Emulate mouse movement to a position (550,5) of element
moveToElement(element,0,0,550,5);
//Emulate  the pressing of the  left mouse button
mouseDown();
//Emulate the releasing of the left mouse button
mouseUp();</code>