Jquery and HTML FormData returns "Uncaught TypeError: Illegal invocation"
Implement new FormData(...)
directly in your $.ajax
call and set contentType: false
and processData: false
. This bypasses the mean "Illegal invocation" error in the jQuery form submission.
Quick Cleanup: Syntax Check
Sometimes it's not about complex issues. It's about the little, noticeable things. Here are some quick common mistakes and their solutions:
Validate your selector
Hit the right target with your jQuery selector:
Correctly retrieve input values
Use .val()
correctly. Copy-paste with caution!
Validate FormData add-ons
Double-check your FormData key-value pairs as these are the messengers of successful data transmission:
Check other potential hiccups
AJAX request errors do creep in from syntactic issues unrelated to FormData. So, wear your detective hat and hunt 'em down.
When files attack: Multiple file uploads
When dealing with multiple files it's advantageous to suit up each file with its own FormData object. This gives every file its autonomous treatment:
Doing this averts common file handling errors and is especially useful when uploading images or docs in bulk, or shipping heavy artillery (if you're a viking).
ProTips: Level Up!
Implement async uploads
Asynchronous uploads spruce up user experience by keeping the app's wheels spinning while the cargo is being shipped:
Cover yourself, use error handling
Use “umbrella” error handling to keep the rain of network issues, file size limits, or oddball response structures at bay. Keeps the app's health sunny!
Communicate with users
Let the users quench their curiosity with real-time updates on upload progress or success. Good relationships are built on good communication, you know!
Security first!
Double check that your server-side scripts run a pat-down security check on the uploaded files. We're trying to keep the malware mob at bay after all.
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