Question

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JS How to use the ?: (ternary) operator

I download one plugin for wordpress in that plugin there is one javascript.
Into that js code I don’t understand how it works.

function ddet_javascript() {

echo '
<script language="JavaScript" type="text/javascript"><!-- 
function expand(param) { 
param.style.display=(param.style.display=="none") ? "" : "none"; 
 } 
  //--></script>';
}

In this code I don’t understand the line given below.

param.style.display=(param.style.display=="none") ? "" : "none";

what is the use of ? and : in this line. please let me know if anyone know about it.

Answer 1

It is an operator:

(condition) ? true : false

It is like:

if(param.style.display=="none")
       param.style.display="";
else
       param.style.display="none;