删除 Javascript 中的所有多个空格，并用单个空格替换

You could use a regular expression replace:

str = str.replace(/ +(?= )/g,'');

Credit: The above regex was taken from Regex to replace multiple spaces with a single space

There are a lot of options for regular expressions you could use to accomplish this. One example that will perform well is:

str.replace( /\s\s+/g, ' ' )

See this question for a full discussion on this exact problem: Regex to replace multiple spaces with a single space

You can also replace without a regular expression.

while(str.indexOf('  ')!=-1)str.replace('  ',' ');

you all forget about quantifier n{X,} http://www.w3schools.com/jsref/jsref_regexp_nxcomma.asp

here best solution

str = str.replace(/\s{2,}/g, ' ');