Python 对html输入有着奇怪的理解_Python_Html_Jinja2

Python 对html输入有着奇怪的理解

python html

Python 对html输入有着奇怪的理解,python,html,jinja2,Python,Html,Jinja2,我在html输入中遇到了一个奇怪的错误，每当我尝试将文本向右对齐，并尝试在输入中现有文本的末尾输入运算符（“+”、“-”、“/”、“*”），它出现在文本的开头这是我的html代码- <!DOCTYPE html> <html lang="en"> <head> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/boo

我在html输入中遇到了一个奇怪的错误，每当我尝试将文本向右对齐，并尝试在输入中现有文本的末尾输入运算符（“+”、“-”、“/”、“*”），它出现在文本的开头

这是我的html代码-

<!DOCTYPE html>
<html lang="en">
<head>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" integrity="sha384-JcKb8q3iqJ61gNV9KGb8thSsNjpSL0n8PARn9HuZOnIxN0hoP+VmmDGMN5t9UJ0Z" crossorigin="anonymous">
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<div class="text-center">

<form  method="post"  action="#" name="cal">
    {%if a=="" %}
        <h3>CAlCULATOR</h3><input type="text" value=""  name="expression" style="width:34.8%" dir="rtl"><br><br>
    {%elif a!=""%}
        <h3>CAlCULATOR</h3><input type="text" value= '{{a}}'  name="expression" style="width:34.8%" dir="rtl"><br><br>
    {%endif%}
    <input type="button" value=" C " class="btn btn-outline-dark" onclick="cal.expression.value = ''" style="width:34.8%" ><br>
    <input type="button" value=" 1 " class="btn btn-outline-dark" onclick="cal.expression.value += '1'" style="width:8.6%">
    <input type="button" value=" 2 " class="btn btn-outline-dark" onclick="cal.expression.value += '2'"  style="width:8.6%">
    <input type="button" value=" 3 " class="btn btn-outline-dark" onclick="cal.expression.value += '3'"  style="width:8.6%">
    <input type="button" value="+" class="btn btn-outline-dark" style="width:7%" onclick="cal.expression.value += '+'" ><br>
    <input type="button" value=" 4 " class="btn btn-outline-dark" onclick="cal.expression.value += '4'" style="width:8.6%" >
    <input type="button" value=" 5 " class="btn btn-outline-dark" onclick="cal.expression.value += '5'" style="width:8.6%">
    <input type="button" value=" 6 " class="btn btn-outline-dark" onclick="cal.expression.value += '6'" style="width:8.6%">
    <input type="button" value="-" class="btn btn-outline-dark" style="width:7%" onclick="cal.expression.value += '-'" ><br>
    <input type="button" value=" 7 " class="btn btn-outline-dark" onclick="cal.expression.value += '7'"style="width:8.6%">
    <input type="button" value=" 8 " class="btn btn-outline-dark" onclick="cal.expression.value += '8'" style="width:8.6%">
    <input type="button" value=" 9 " class="btn btn-outline-dark" onclick="cal.expression.value += '9'" style="width:8.6%">
    <input type="button" value= "*" class="btn btn-outline-dark" style="width:7%"onclick="cal.expression.value += '*'" ><br>
    
    <input type="submit" value="=" style="width:26.9%"class="btn btn-outline-dark" >
    <input type="button" value="/" class="btn btn-outline-dark" style="width:7%" onclick="cal.expression.value += '/'" >

</form>
</div>

<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js" integrity="sha384-9/reFTGAW83EW2RDu2S0VKaIzap3H66lZH81PoYlFhbGU+6BZp6G7niu735Sk7lN" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js" integrity="sha384-B4gt1jrGC7Jh4AgTPSdUtOBvfO8shuf57BaghqFfPlYxofvL8/KUEfYiJOMMV+rV" crossorigin="anonymous"></script>
</body>
</html>

import time as t
a=Flask(__name__)
akl=True
ans=""
@a.route('/')
def hp():
    return render_template("now.html")
@a.route('/calculator',methods=["POST","GET"])
def hpq():
    if request.method=="POST":
        try:
            k=f"{eval(request.form['expression'])}"
        except :
            k="invalid expression"
        
    
        return render_template("par2.html",a=k)
    else:
        return render_template("par2.html")

if __name__ == "__main__":

    a.run(debug=True)```