How to avoid pop up block ?

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C#

Javascript

jQuery

I using the below code to show popup in new window

var  popupWindow = window.showModalDialog(
    'Edit.aspx?ppId = ' + s,
    "_blank",
    'left=300, top=200, height=350, width= 550, status=yes, resizable= yes, scrollbars= yes, toolbar= no,location= center, menubar= no'
);

but the popup getting blocked by the browser ... I need to manually allow popups every time...
Please say some solution to avoid popup block