如何使用javascript为每行文本添加前缀/后缀？

Question

how would i add a prefix per line to a text area.. example:

this is the content of the textarea:

hello
124

and i would want to add a [b] prefix and suffix to each line so that when i click a button the result will be:


[b]hello[/b]
[b]124[/b]

please help me :(

Answer 1

Using only plain Javascript, you can do:

var textArea = document.getElementById("yourTextAreaID");
var lines = textArea.value.split("\n");
for (var i = 0; i < lines.length; ++i) {
    lines[i] = "[b]" + lines[i] + "[/b]";
}
textArea.value = lines.join("\n");

Or, as @Alin Purcaru suggested, without using a loop:

var textArea = document.getElementById("yourTextAreaID");
textArea.value = "[b]" + textArea.value.split("\n").join("[/b]\n[b]") + "[/b]";

Answer 2

text = document.getElementById("the_textarea").value;
document.getElementById("the_textarea").value = text.replace(/.+/g, "[b]$&[/b]");

Example:

Answer 3

using joins and splits:

var prefix = '[b]', suffix = '[/b]',
   txt = document.getElementById('myText');
txt.value = prefix + txt.value.split('\n').join(suffix + '\n' + prefix) + suffix;

Answer 4

<script language="javascript" type="text/javascript">
function TextDefine(val){
var i= 0;                

var array1 = val.value.split("\n");
for ( i = 0; i < array1.length; i++) {
    array1[i] = "[b]" + array1[i] + "[/b]";
}
val.value = array1.join("\n");

}
</script>

<textarea name="data" id="data"></textarea>
<input type="button" name="submit1" value="Submit" onclick="TextDefine(document.getElementById('data'))" />

Answer 5

1. Convert the string into an array starting at position 1 of the array.
2. Push the prefix at position 0 of the array.
3. Convert the array back to a string with join.