<textarea name="description" onKeydown="limitCount(this)" ></textarea>
function limitCount(textareaObject){
if(textareaObject.value.length>10)
event.returnValue=false
}
<textarea name="description" onKeydown="limitCount(this)" ></textarea>
function limitCount(textareaObject){
if(textareaObject.value.length>10)
event.returnValue=false
}