Form verification solution-php Tutorial

If the form verification fails to be submitted after registration, the system automatically returns to the registration page. how can I save the information filled in before the user submits it? Especially the information in select? ------ Solution ------------------ try the history. back (); ------ solution -------------------- after submission, it is okay to assign values to each form using js? Form verification
If it fails to be submitted after registration, the system automatically returns to the registration page. how can I save the information filled in before submission? Especially the information in select?

------ Solution --------------------
Try js's history. back ();
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After submission, why not assign values to each form using JS?