Index of selected words using Javascript

问题

How can I get the index of selected text in HTML using Javascript? For example, in an HTML file, there is paragraph like the following:

I am living in India. India is the very beautiful country.

Now if the user selects India in the first sentence then there should be an alert 5 and if the user selects India of second line then there is an alert 6.

How can I get the index of the word that the user selected?

回答1:

You could do this with the new TextRange module of my Rangy library. Rangy's Range object has moveStart() and moveEnd() methods which allow you to expand the range a word at a time in either direction.

Here's a demo: http://jsfiddle.net/timdown/ArMHy/

Code:

var sel = rangy.getSelection();
if (sel.rangeCount > 0) {
    var range = sel.getRangeAt(0);

    // Expand the range to contain the whole word
    range.expand("word");

    // Count all the preceding words in the document
    var precedingWordCount = 0;
    while (range.moveStart("word", -1)) {
        precedingWordCount++;
    }

    // Display results
    alert("Selection starts in word number " + (precedingWordCount + 1));        
}

回答2:

If you want to find a string by its index, you can use-

string.match(regularExpression)[index]

Parameter Values-

regularExpression = Required. The value to search for, as a regular expression.

index = index of the regularExpression.

Now you can consider this as an object and assign event handlers to it.

来源：https://stackoverflow.com/questions/11074017/index-of-selected-words-using-javascript