trying to clear value in textbox in javascript function

Question

i am trying to put validation on a textbox onkeyup. Textbox should contain only 5 digit value and after decimal only upto 4 decimal places. eg,12345 ,12345.2345 if user enter value other than regex then the texbox should become blank and i want it to be done in function and this function should be generic so that any other can use this function .Aspx

<input type="number" id='inpSurfIndN' value='' runat="server" onkeyup="isFloatNumber(this.value)" />

Script function

<script type="text/javascript">
function isFloatNumber(value) {
 var regex = /^[0-9]\d{0,4}(\.\d{1,4})?%?$/
            var regmatch = regex.test(value);
            if (regmatch == null|| regmatch==false) {
                alert("Please fil correct expression");
                value = "";
                return false;
            }
            return true;
        }
</script>

Did you try $('#inpSurfIndN').val("") instead of value = ""? — Jitendra G2
– Jitendra G2, Commented Sep 20, 2018 at 5:25
@JitendraRangpariya actually i want it to be generalised i mean if there will be five different textbox and all have same function so i want it to make generic.no need to write different function for different textbox keyup event. — Mohan
– Mohan, Commented Sep 20, 2018 at 5:28
you can pass 'event' parameter to isFloatNumber function and then when it executes function isFloatNumber, eve argument contains the element on which the function is called. Refer to my answer in detail — Shikha thakur
– Shikha thakur, Commented Sep 20, 2018 at 5:35

Smit Raval · Accepted Answer · 2018-09-20 05:33:41Z

2

function isFloatNumber(elem) {
 var regex = /^[0-9]\d{0,4}(\.\d{1,4})?%?$/
            var regmatch = regex.test(elem.value);
            if (regmatch == null|| regmatch==false) {
                alert("Please fil correct expression");
                elem.value = "";
                return false;
            }
            return true;
        }

<input type="number" id='inpSurfIndN' value='' runat="server" onkeyup="isFloatNumber(this)" /> 
<input type="number" id='inpSurfIndN1' value='' runat="server" onkeyup="isFloatNumber(this)" /> 
<input type="number" id='inpSurfIndN2' value='' runat="server" onkeyup="isFloatNumber(this)" />

You can use above snippet which will work for n numbers of inputs.

answered Sep 20, 2018 at 5:33

Smit Raval

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Comments

Suresh · Accepted Answer · 2018-09-20 05:36:37Z

0

Updating value = ""; doesn't update the UI element. You should access the UI Element object by passing this and update the value like this.value = " " else you should use the selectors like document.getElementbyId() to access those object like document.getElementbyId('inpSurfIndN').value = ""

answered Sep 20, 2018 at 5:36

Suresh

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Comments

Jitendra G2 · Accepted Answer · 2018-09-20 05:37:14Z

0

One of way you can use below logic,

function isFloatNumber(obj) {
  var regex = /^[0-9]\d{0,4}(\.\d{1,4})?%?$/
  var regmatch = regex.test(obj.value);
  if (regmatch == null || regmatch == false) {
    alert("Please fil correct expression");
    obj.value = "";
    return false;
  }
  return true;
}

<input type="number" id='inpSurfIndN' value='' runat="server" onkeyup="isFloatNumber(this)" />

answered Sep 20, 2018 at 5:37

Jitendra G2

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Comments

Jignesh Sanghani · Accepted Answer · 2018-09-20 05:40:25Z

0

var n = document.getElementById("numPeople"),
    r = document.getElementById("result");

n.addEventListener("keyup", function(e) {

    var regex = /^[0-9]\d{0,4}(\.\d{1,4})?%?$/
            var regmatch = regex.test(n.value);
            if (regmatch == null|| regmatch==false) {
                alert("Please fil correct expression");
                n.value='';
                return false;
            }
}, false);

<input id="numPeople" type="number" min="0" value="" placeholder="Pick a number" />

answered Sep 20, 2018 at 5:40

Jignesh Sanghani

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Comments

Shikha thakur · Accepted Answer · 2018-09-20 05:40:43Z

0

You cannot access the value variable which is passed as a parameter, it doesnt reference to the value of the input box Instead you can access the element and change the value like below:

 function isFloatNumber(eve) {
            var regex = /^[0-9]\d{0,4}(\.\d{1,4})?%?$/
            var regmatch = regex.test(value);
            if (regmatch == null|| regmatch==false) {
                alert("Please fil correct expression");
                var elem = eve.currentTarget;                 
                elem.value = "";
                return false;
            }
            return true;
        }

edited Sep 20, 2018 at 5:40

answered Sep 20, 2018 at 5:30

Shikha thakur

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1 Comment

Niclas Lindqvist Over a year ago

I think you need meant eve.currentTarget or function isFloatNumber(e).

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