How the onclick receives the variable that JS passes over

How does the onclick receive the variable that JS passes over?
Html:


Js:

I want to put JS finally get dtitles value as a parameter to the action to pass to the do.php page, how to write this JS value in the onclick event?

------Solution--------------------
Dtitles=json.stringify (glob_oplist);
window.location.href= ' do.php?action= ' +dtitles;
------Solution--------------------
$ (function () {
$ ("#btn_test"). attr ("OnClick", "alert (1)");
});
The LZ can override the button's OnClick property value when the page is loaded by the method above.
Put your parameters in.

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