How to make a general java script function to prevent entering letters into a text box

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Im am using a javascript function to prevent entering letters into a text box on my site... The code looks like this

C#

function checkInp() {

            var x = document.forms["form1"]["txtIfCh1"].value;
                if (isNaN(x)) {
                    alert("Треба да внесувате број!");
                    return false;
                }

        }

and I add onkeypress="checkInp()" tho the text box...

this code works fine, but i have 10 textboxex to check for letters.. How can the functiont be changed in the way that i will have jsut oune function not 10.??

Posted 17-Nov-14 21:38pm

Voley

Updated 5-Jan-22 19:33pm

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2 solutions

Solution 2

I have an additional problem with the function:

C#

function checkInp() {
            var input = document.getElementsByTagName("input");
            for (var i =0; i < input.length; i++) {
                if (input[i].type == "text") {
                    if (isNaN(input[i].value)) {
                        alert("Треба да внесувате бројка!");
                        return false;
                    }
                }
            }
        }

this fucntion works finde till I have to input negative numbers and decimal numbers wich I separet them with comma (,) ex: -12.3 or -3,4 ... How can I exclude , and - to recognize them as caracters?

Posted 27-Nov-14 4:16am

Voley

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Peter Leow · Accepted Answer · 2014-11-17T22:23:00

Solution 1

Try this:

XML

<!DOCTYPE html>
<html>
<head>
<script>
function checkInp() {
 var input = document.getElementsByTagName("input");
 for (var i = 0; i < input.length; i++) {
    if (input[i].type == "text"){
        if (isNaN(input[i].value)){
           alert("Not a number!");
            return false;
        }
    }
 }
}
</script>
</head>
<body>
<form onsubmit="return checkInp();">
<input type="text" id="textbox1" value="">
<input type="text" id="textbox2" value="">
<input type="submit" value="submit">
</form>
</body>
</html>

Posted 17-Nov-14 22:23pm

Peter Leow

Updated 17-Nov-14 22:26pm

v4

Comments

Voley 18-Nov-14 7:00am

Thankyou, the function was helpful :)

Peter Leow 18-Nov-14 7:46am

You are welcome.

Voley 27-Nov-14 10:17am

I have an additional problem with the function:

function checkInp() {
var input = document.getElementsByTagName("input");
for (var i =0; i < input.length; i++) {
if (input[i].type == "text") {
if (isNaN(input[i].value)) {
alert("Not Number");
return false;
}
}
}
}

this fucntion works finde till I have to input negative numbers and decimal numbers wich I separet them with comma (,) ex: -12.3 or -3,4 ... How can I exclude , and - to recognize them as caracters?
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