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Checking number using isNaN function |
JavaScript has one important function isNaN() to check any data is number or string. This function isNaN() is remembered as short form is Is Not a Number. This function returns true if the data is string and returns false if the data is a number. Here is one simple example to check one string. We will use one if else condition check to display a message accordingly. Here is the code.
var my_string="This is a string";
if(isNaN(my_string)){
document.write ("this is not a number ");
}else{document.write ("this is a number ");
}
We will integrate this function to one JavaScript prompt. Here we will ask the user to enter a number. The value entered by user we will check by isNan function and display message accordingly. Here is the code.
var my_string = prompt("Please enter a number","");
document.write(my_string)
if(isNaN(my_string)){
document.write ("this is not a number ");
}else{document.write ("this is a number ");
}
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