Uncaught TypeError: Cannot read property 'value' of null
I am unsure which of them is wrong because you did not provide your HTML, but one of these does not exist:
var str = document.getElementById("cal_preview").value;
var str1 = document.getElementById("year").value;
var str2 = document.getElementById("holiday").value;
var str3 = document.getElementById("cal_option").value;
There is either no element with the id cal_preview, year, holiday, cal_option, or some combination.
Therefore, JavaScript is unable to read the value of something that does not exist.
EDIT:
If you want to check that the element exists first, you could use an if statement for each:
var str,
element = document.getElementById('cal_preview');
if (element != null) {
str = element.value;
}
else {
str = null;
}
You could obviously change the else statement if you want or have no else statement at all, but that is all about preference.
how to fix the Uncaught TypeError: Cannot read property 'Value' of null
value should be in lower case. Thats why you get undefined when you get document for nameField node value. for nameField.
let nameField = document.getElementById("nameField").value;
How to fix 'Cannot read property 'value' of null' with an input in Javascript
Use window.onload and call a function, which performs all the tasks you want. It will wait till window loads and then your function will be executed. Right now it is getting executed before the html is getting rendered, means it is accessing the value of the slider before even it is loaded. So you get the error.
window.onload=function(){var grayscale = document.getElementById('grayscale');console.log(grayscale.value)
grayscale.onchange = function(){ console.log(grayscale.value)}}<input type='range' id='grayscale' min='0' max='100'>Uncaught TypeError: Cannot read property 'value' of null when it exists
After correcting the # issue, make sure you aren't trying to find the element before the DOM has loaded the element. Place your <script> just before the closing of the body (</body>) because, by the time the parser reaches that point all the elements will have been parsed.
This won't work:
<body>
<script> // This won't work because, the HTML element hasn't been reached by the parser yet. var myname = document.getElementById("text_name").value;</script>
<form class="complex_form" id="create_text"> <div class="texttitle">Send</div> <input id="text_name" type="text" class="form_element" placeholder="text" name="my_text" required/> <textarea rows="5" id="actual_text" class="form_element" name="actual_text" placeholder="Text" required></textarea> <button type="submit" class="btn">Send text</button></form>
</body>Cannot read property 'value' of null Error in first render
Check the solution bellow:
import React from "react";
function RechartsInputs() {
const Period = document.getElementById("Period");
console.log(Period);
const inputHandler = (e) => {
console.log(e.target.value);
};
return (
<div>
<label>Period:</label>
<select id="Period" onChange={e => inputHandler(e)}>
<option>Last 12 month</option>
<option>Last 9 month</option>
<option>Last 6 month</option>
<option>Last 3 month</option>
<option>Last month</option>
</select>
</div>
);
}
export default RechartsInputs;
hope it helps ;D
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