CODEWITHSUNDEEP
javascriptvalidation
Darren Burgess
Darren Burgess

Reputation: 4312

check if string contains only numbers, else show message

I have a simple form, which performs a calculation when a digit is pressed, however this should only happen when numbers are typed, if a letter is added i would like for a notification to appear. Is there a simple function to do this?

Form

    <input onKeyPress="return onlyNumbers()" onKeyUp="calc()" id="value1" type="text" name="value1">
    <select onChange="calc()" id="manipulator" name="manipulator">
        <option value="commission">Commission</option>
        <option value="cost">Return</option>
    </select>
</form>

calc function

function calc(){
    if (window.XMLHttpRequest){// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
    } else {// code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }

    val1 = document.getElementById("value1").value;
    mani = document.getElementById("manipulator").value;

    if (val1 != ""){
        document.getElementById("resp").innerHTML="Calculating...";
        queryPath = "comCalcServ.php?value1="+val1+"&manipulator="+mani;

        xmlhttp.onreadystatechange=function(){
            if (xmlhttp.readyState==4 && xmlhttp.status==200){
                document.getElementById("resp").innerHTML=xmlhttp.responseText;
            }
        }

        xmlhttp.open("GET",queryPath);
        xmlhttp.send();
    }
}

I am currently looking at the isNaN function but not familiar with the JS syntax so unsure where to use it.

Upvotes: 4

Views: 24007

Answers (3)

shreedhar bhat
shreedhar bhat

Reputation: 4825

Try this simple one

if(val1.match(/^\d+$/)) {
    // your code
}

Upvotes: 1

kaustubh
kaustubh

Reputation: 21

the above code did not work in my case . so i made few changes . i just changed regex to /^[0-9]*$/.test(val1) and it worked.

Upvotes: 0

Sudhir Bastakoti
Sudhir Bastakoti

Reputation: 100175

Do you mean:


//add inside your calc function
val1 = document.getElementById("value1").value;
if(/^\d+$/.test(val1)) {
 //proceed with rest of code
}
else {
 alert("Invalid");
 return false;
}

Upvotes: 7

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