How to check if certain row in textarea is empty?

Question

How to check if certain row in textarea is empty with javascript?

<script type="text/javascript" src="../../../js/jquery-1.3.2.min.js"></script>
<script>
$(document).bind('keydown',function (e) {

if(e.which==13) {
function isRowEmpty( idOfTextArea , row ){

  return $("#" + idOfTextArea )[0].value.split("\n")[row-1] == "";

}
alert(isRowEmpty("txtarr",3));

    }
});
</script>
<textarea id="txtarr" rows="30" ></textarea>

But it returns always false

Answer 1

use string.split("\n", limit), where string is the textarea value.

Then, use your standard FOR loop, and do something like if (list[i].match("/(\s)/")) to check for a line that is only whitespace.

Answer 2

<script type="text/javascript">
<!--
function rows() {
var lines;
var TA=document.form1.textarea1.value;
if(document.all) { // IE
lines=TA.split("\r\n");
}
else { //Mozilla
lines=TA.split("\n");
}
for(var i=0; i<lines.length; i++) {
    if (lines[i].replace(/^\s+|\s+$/, '').length == 0) {
        alert('Line ' + i + ' is empty')
    }
}
}
//-->
</script>

Answer 3

//Assumes you use jQuery or equivalent
function isRowEmpty( idOfTextArea , row ){

  return $("#" + idOfTextArea )[0].value.split("\n")[row-1] == "";

}