Here i will share some useful jQuery validation properties and functions with you, like counting the length of an element, allowing alphanumeric and numbers only values to an input element.
1- Count length of an input box value ?
$(id).val().length
jQuery length property is use to calculate the total element in the jQuery object.
Example
function checklength(id){
var no=$(id).val.length;
alert(no);
}
<input type="text" id="name" onBlur="checklength(this.id)" />
when you focus out of the input box checklength() function calculate the length of your input box value and retrun you in alert box.
2: Check alphanumeric value
function isAlphaNumeric(value){
var expression=/((^[0-9]+[a-z]+)|(^[a-z]+[0-9]+))+[0-9a-z]+$/i;
if(value.match(expression)){
alert("Value is alphanumeric");
return true;
}
else{
alert("Value is not alphanumeric");
return false;
}
}
<input type="text" id="name" onBlur="isAlphaNumeric(this.value)" />
when you focus out of the input box, the above function match your input box value with the defined regular expression “/((^[0-9]+[a-z]+)|(^[a-z]+[0-9]+))+[0-9a-z]+$/i;”. if it will match with it, it return you true otherwise alert box.
3: Allow numbers only to an input field
function chk() {
var key=window.event.keyCode;
if(key>57 || key<48) {
window.event.returnValue=false;
alert("Enter numbers only");
}
}
<input type="text" id="name" onKeypress="chk()" />
key 57 is the code of number 9 and key 48 is the code of number 0, so it check that the press key is greater than 9 and less than 0, it returns a alert box with the defined message.
4: How to check blank space
function chkspc()
{
var key=window.event.keyCode;
if(key==32)
{
window.event.returnValue=false;
alert("Space not allowed");
}
}
key 32 is the code of space key , so it check that the press key code is equal to 32, it returns a alert box with the defined message.
<input type="text" id="name" onKeypress="chkspc()" />
So Guys if feel any problem with these functions, you can leave it on comment. I will try to reply you and thank you to read our blog. Keep visiting
