Question

183

javascript error [object HTMLInputElement][object HTMLInputElement]

rated 0 times [ 185] [ 2] / answers: 1 / hits: 27526 / 8 Years ago, mon, december 19, 2016, 12:00:00

i am practicing java script code but having issue while implementing this code.

<html>

<body>

<script>  

function f2(){

var a=document.getElementById(a);

var b=document.getElementById(b);

var c=a+b;

document.write(c);

}

</script>  



Enter A:<input id=a type=text name=txt1 ><br>

Enter B:<input id=b type=text name=txt2 ><br>

<button type=button onclick=f2()>Sum Here</button>

</body>

</html>

When I add two numbers then it shows error like [object HTMLInputElement][object HTMLInputElement].

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alli

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answered 8 Years ago reed · Accepted Answer

The value property of input elements is used to retrieve the value enters in the input. This value will be a string.

Since you want to add numbers, it is better you check if the inputs entered are numbers to avoid unwanted bugs.
There are many ways to check this, one I've used it by adding '+' sign in front of the entered string value, this will convert a number in string to a number and then check for NaN.

here is the fiddle and code
https://jsfiddle.net/7sgcmfu8/

<script>  

function f2(){

var a= +document.getElementById(a).value;

var b= +document.getElementById(b).value;

if(!isNaN(a) && !isNaN(b)){

    document.write(a+b);

}else{

    document.write(enter numbers);

}

}

</script>  



Enter A:<input id=a type=text name=txt1 ><br>

Enter B:<input id=b type=text name=txt2 ><br>

<button type=button onclick=f2()>Sum Here</button>