I have a text field like this:
<input id="num" type="text" style="width:10px"/>
I am trying to retrieve it from JavaScript as follows:
var numofnodes =parseInt(document.getElementById('num').value,10);
It is giving "", and i tried like this
var numofnodes =document.getElementById('num').value
But still I am getting "".
Problem seems that you are trying to read the value on page load, i.e. textbox isn't having any value given, hence you get blank:
var numofnodes = parseInt(document.getElementById('num').value, 10);
alert(numofnodes);<input id="num" type="text" style="width:10px" />Try with value attribute for default no. of nodes:
var numofnodes = parseInt(document.getElementById('num').value, 10);
alert(numofnodes);<input id="num" type="text" style="width:10px" value="100" />parseInt either returns an integer or NaN, it shouldn't be a "". How do you output the value that you get? Your code seems to works fine for me:
<input id="num" type="text" style="width:100px"/>
<button id="b">log value</button>
...
document.getElementById("b").onclick = function() {
console.log( parseInt(document.getElementById('num').value, 10) );
}
I tried your code, and for me it works correctly.
<input id="num" type="text" style="width:10px;" value=100 />
added value into attribute
$(document).ready(function() {
// print into console as int
var numofnodes =parseInt(document.getElementById('num').value,10);
console.log(numofnodes);
// print into console as string
var numofnodes =document.getElementById('num').value
console.log(numofnodes);
});
Hmm, surprisingly enough, no one mentioned the event's built-in property for this.
event.target.valueAsNumber
will give the value as a number for inputs with type number without any conversions.
id="num"attribute? Any errors in the console?