How to know if the text in a textbox is selected?

Question

I have text boxes <input type='text'> that only allow numeric characters and wont let the user enter a dot (.) more than once. Problem is, if the text in the text box is selected, the user intends to overwrite the contents with a dot, hence making it allowed! The question is, how can you tell in javascript whether the text in that text box is selected or not.

Thanks

Answer 1

The following will tell you whether or not all of the text is selected within a text input in all major browsers.

Example: http://www.jsfiddle.net/9Q23E/

Code:

function isTextSelected(input) {
    if (typeof input.selectionStart == "number") {
        return input.selectionStart == 0 && input.selectionEnd == input.value.length;
    } else if (typeof document.selection != "undefined") {
        input.focus();
        return document.selection.createRange().text == input.value;
    }
}