Question

4

Javascript - onblur function cannot change the value of the textbox

rated 0 times [ 5] [ 1] / answers: 1 / hits: 33247 / 12 Years ago, mon, september 10, 2012, 12:00:00

I have some textboxes allowing users to enter numbers from 0 to 20. So that I have a js validation code to test if they follow the rule or not.

I have such the following textboxes:

<input type=textbox name=tx1 onblur=checkValue(this.value) />

<input type=textbox name=tx2 onblur=checkValue(this.value) />

....

Then I write a js function like this:

function checkValue(value) {

  if (value > 20) {

     return this.value = 20;

  } else if (value < 0){

     return this.value = 0;

  } else if (value == '' || isNan(value)) {

     return this.value = 0;

  } else {

     return this.value;

  }

}

I tried to test via console.log(). I tried alert('hi') and it works. However, it does not change value at all when meeting the above conditions. So could anyone help me to solve this?

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quinn

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1 Year ago

answered 12 Years ago harleew · Accepted Answer

Try this

<input type=textbox name=tx1 onblur=checkValue(this) />

function checkValue(sender) {

var value = parseInt(sender.value);

  if (value > 20) {

     sender.value = 20;

  } else if (value < 0){

     sender.value = 0;

  } else if (value == '' || isNan(value)) {

     sender.value = 0;

  } else {

     return sender.value;

  }

}