Try this:
<script type="text/javascript">
function CheckPlugin()
{
var is_chrome = navigator.userAgent.toLowerCase().indexOf('chrome') > -1;
function findPlugin(ext) {
var thisExt, findExt;
for (var n = 0; n < navigator.plugins.length; n++) {
for (var m = 0; m < navigator.plugins[n].length; m++) {
thisExt = navigator.plugins[n][m].description.toLowerCase();
findExt = thisExt.substring(0, thisExt.indexOf(" "));
if (findExt == ext)
return (true);
}
}
return (false);
}
if (is_chrome ==true) {
if (findPlugin("acrobat")) {
return true;
}
else {
alert("please disable the chrome pdf viewer and enable the Adobe Acrobat PDF viewer \n Please follow the steps:\n 1.Open the new tab 'chrome://plugins/' type the Address. \n 2. Click the Enable link in 'Adobe Acrobat' field. \n 3. click the Disable link in 'Chrome PDF Viewer'. \n 4. Close the tab and you can open the PDf files in chrome browser.");
return false;
}
}
else {
}
}
</script>