I need help in sending data from variable derived in JavaScript to flaks route. I have submit button, on which I have flask route and I am passing variables encloses in {{}}.
One of the variable selectedItem is derived inside JavaScript. I get right value on alert but when route is called it’s coming as None. Am I doing something wrong here? May be html submit is not able to refer to JavaScript variable? If I pass hardcoded value to my route parameter it works fine.
Please help. Thank you
function test_alert(e){ alert("tis is test"+e.value) selectedItem=e.value; }If you want to transfer your javascript variable to your flask route kindly check my answer here:
Why does my data come from request.form when passing it to the backend in Flask, python?
JavaScript
var your_data = {
/* name */ : /* value */
}
fetch(`${window.origin}/your_url`, {
method: "POST",
credentials: "include",
body: JSON.stringify(your_data),
cache: "no-cache",
headers: new Headers({
"content-type": "application/json"
})
})
Python
@app.route("/your_url", methods = ["post"])
def printer():
data = request.get_json()
print(data)
return "TODO"
However if you want to render a template (like a form submit would do) then you can do this:
A. Doing it inside a hidden form
HTML
<form id="mainform" action="/your_url" method="post">
<input type="hidden" name="jsvar" id="jsvar" value="" />
<button type="submit">Click Me</button>
</form>
JavaScript
var form = document.getElementById("mainform")
var input = document.getElementById("jsvar")
form.addEventListener('submit', function(e){
input.value = "your_var"
form.submit()
})
Python
@app.route("/test",methods=["POST"])
def proposeswap_db_function():
print("inside function")
data = request.form["jsvar"]
print(data)
print('rendering mainmenu')
return f"{data}"