Removing Double space from a textbox using REGEX

Input:

"I want         to   remove        double     space    from    textbox."

Output:

"I want to remove double space from textbox."

function valid(f) {
     return f.replace(/^\s+开发者_开发知识库|\s+$/g,'').replace(/\s+/g,' ');
}

I have called this event onblur="valid(this);"

You need to be accessing the value of the input... in your above code you're trying to run a regex on an input object.

function valid(f) {
     f.value=f.value.replace(/^\s+|\s+$/g,'').replace(/\s\s+/g,' ');
     return true;
}

Try:

return f.replace(/ +/,' ');

You have to get the value of the textbox, and put the result back in the value:

onblur="this.value = valid(this.value);"