如何防止通过表单输入提交字符

Question

I'm in the process of creating a gambling website, but currently with the betting form input you can type a negative number etc (-100) and you will have 100 coins put into your balance.

I need to restrict the use of anything but number digits being used within the input. Currently my work around is blocking the user from typing in anything other than numbers but you are able to hop into the developer tools and insert the value manually.

I believe i need to have an onSubmit validation for the input which says if anything but numbers are inserted do not allow the submit.

I'm not sure how i will do this, thanks for the help!

Answer 1

put onkeypress="return onKeyValidate(event,alpha);" on your input box,and         
call the function

function onKeyValidate(e,charVal){
var keynum;
var keyChars = /[\x00\x08]/;
var validChars = new RegExp(charVal);
if(window.event)
{
    keynum = e.keyCode;
}
else if(e.which)
{
    keynum = e.which;
}
var keychar = String.fromCharCode(keynum);
if (!validChars.test(keychar) && !keyChars.test(keychar))  
{
    return false
} else{
    return keychar;
}

}

Answer 2

Use ctype_digit()

//returns true
<?php
if (ctype_digit('123')) {
    echo 'true';
} else {
    echo 'false' ;
}
?>


//returns false
<?php
if (ctype_digit('-123')) {
    echo 'true';
} else {
    echo 'false' ;
}
?>

Answer 3

you can use this reguler expression to validate for numbers

samp html <button type="submit" onclick="myfunc()">Click Me!</button>

function myfunc(){
var a = /^\d*$/;
{
if(!a.test(value of input))
{
    alert('Please provide a Number');
    return false;
}
} 
}

here

• / at both ends mark the start and end of the regex
• ^ and $ at the ends is to check the full string than for partial matches
• d* looks for multiple occurrences of number charcters

if you want only positive numbers use this /^[+]?([0-9]+(?:[\\.][0-9]*)?|\\.[0-9]+)$/

Answer 4

this jquery code can solve your problem

$(function(){
        $("#submit").click(function(evnt){
            var inptTxt = $("#myField").val();

            if(check(inptTxt)){
                //your test true then submits
                $('#form').submit;
            }else{  //test failed
                evnt.preventDefault();
            }
        })
    })

here the #submit is the id of submit button and #form is the id of the form to be submitted